Figs. 91 and 92 show respectively the manner of 'easing' by removal of the wall, and by thinning the web of the shoe. In this connection it is necessary to point out that on no account should 'springing' of the heels of the shoe be allowed. Fig. 93 illustrates the ill-practice.

In this case, when the entire weight is thrown on to the heels, the portion of wall posterior to the crack is bound to participate unduly in the downward movement, and so tend to widening of the crack at its highest point.



We have already referred to the matter of 'clips.' In no case, whether the crack be at the toe or in the quarters, should a clip be placed immediately below it. If the crack is at the toe, the usual clip should be dispensed with, and a clip at each side made to take its place. At the same time care should be taken to avoid throwing the weight far forward. For that reason a shoe with calkins or with very high heels should be removed, and a shoe with an ordinary flat web substituted.

In the case of quarter-crack, where the constant movement of the parts under expansion and contraction of the foot makes itself most felt, it is wise to apply a shoe with clips fitting moderately tight against the inside of the bars. By this means movement will to a very large extent be curtailed.

Where a marked tendency to contraction is found, as is often the case with quarter-crack, then the shoe with the clips may be rendered more marked in its operation by giving to the outer face of each clip—that face applied to the bar—a slope from above downwards and outwards. In other words, a slipper shoe should be applied and the contraction given equally as much attention as the sand-crack itself.

Where the crack is situated far back in the quarter, and easing of the bearing cannot be accomplished without tending to spring the heels, then the most suitable shoe is a bar shoe. With it the bearing may, of course, be eased in exactly the position required, and the heels still allowed to take their fair share in bearing the body-weight, and thus assist in closing the crack. The bar shoe, if properly fitted, gives us also a bearing on the frog, and aids greatly in counteracting contraction.

2. Curative.

(a) The Application of Dressings to the Lesion.—In the case of a recent crack, deep, and attended with haemorrhage, the foot should be thoroughly cleansed. Where possible, a constant flow of cold water from a hose-pipe should be allowed to run over the foot. By this means the inflammatory symptoms will be held in check and pain prevented. Later the shoe may be eased at the required place, and a blister applied to the coronet. This, with rest, will sometimes prove all that is needed.

Should a crack be of old standing, and complicated by the presence of pus, a course of hot poulticing will often prove of benefit. The poultice should be medicated with any reliable disinfectant, and should be renewed, or at any rate reheated, two or three times daily. The crack itself should be thoroughly cleaned after the removal of each poultice, and a concentrated antiseptic solution—such as Tuson's spts. hydrarg. perchlor., carbolic acid, and water, (1 in 10) or liquor zinci chlor.—poured into it. On discontinuing the poulticing, the strength of the antiseptic solutions may be decreased, the parts rested by correct shoeing, and a blister applied to the coronet as before.

If these measures alone should prove insufficient, then the surgeon will either fall back on those we have just related, or proceed to methods next to be described.

(b) Immobilizing the Crack by Means of grooving the Wall.—To our minds, this is as ready and withal as successful a method of dealing with sand-crack as has yet been devised. It may be done in a variety of ways: (1) By two grooves arranged about the crack in the form of a V, as Fig. 94; (2) by a perpendicular groove on either side of the crack, about 1 inch in distance from it, and parallel with the horn fibres, as Fig. 95; (3) by a single horizontal groove at the extreme upper limit of the crack; (4) by drawing two horizontal grooves, one at its upper and one at its lower end (see Fig. 96).



The points to be observed in carrying out this line of treatment are simple enough. In all cases see that the crack is rendered as clean as possible by the use of suitable dressings, and if an excess of horn is present immediately around it, as in the case of a long-standing and complicated lesion, have it thinned down by rasping.

All that is then needed is one or two moderately sharp, flat firing-irons. The groove is then burned into the horn in the positions indicated, and that portion of the wall containing the sand-crack thus prevented from participating in the movements of the foot. For our own part, we consider the V-shaped incision, or either of the horizontal methods of grooving, preferable to lines running in the direction of the horn fibres. With the latter there is certainly a greater tendency to the formation of new cracks than with either of those we advocate. The V-shaped incision we consider most suitable of all, for the reason that by its means a greater degree of immobility is conferred upon the necessary portion of the wall.

Whichever method is adopted, care should be taken to carry the grooves deep enough into the horn, taking them down as near as possible to the sensitive structures. At the same time, especial care should be exercised in not carrying them too deep at their extreme upper limit, or in that case the liability to the formation of fresh cracks in those positions will be greatly increased.

After grooving, a sharp blister should be applied to the coronet every three or four weeks, and the animal, if free from lameness, put to work.

(c) By stripping away a V-shaped Portion of the Wall around the Crack.—This method is only indicated when the crack is greatly complicated by the presence of pus, or by the growth of adventitious horn on the inner surface of the wall. A radical cure is thus obtained, but the animal for a longer time incapacitated from work.

The operation is best performed by first grooving a line to connect the points a and c (Fig. 97). This should run immediately under the coronary margin of the wall, and should stop short of injuring the coronary cushion beneath. Grooves forming the sides ab and bc of the triangular piece of horn are next made, and the horn contained within the lines ab, bc, and ca, carefully removed. The grooves are the easiest made by a cautious use of the firing-iron. The greater thickness of the horn may thus be penetrated, and the grooves afterwards carried to their full and requisite depth by the use of the drawing-knife.

With the removal of the horn the diseased structures are exposed to view. All such should be removed by a free use of the scalpel, and a suitable dressing afterwards applied. A necessary factor in the treatment is the employment of pledgets of antiseptic tow. With these the exposed tissues are covered, and the successive turns of a bandage run tightly over them, so as to exert a moderate degree of pressure. When haemorrhage has accompanied the operation, this dressing should be removed on the following day, the wound dressed, and the pledgets of tow and the bandage renewed. Any after-dressing need only then be practised at intervals of a week. Repair after this operation is rapid, and takes place both from the exposed podophyllus membrane and from the coronary cushion.



(d) By stripping the Wall from the Coronary Margin to its wearing Edge on Either Side of the Crack.—This is merely a more extensive application of the method just described, and is only indicated in a complete and complicated crack that has refused to yield to other modes of treatment (see Fig. 98).

As in the previous case, a groove is run from a to c. The grooves ab and de are then continued to the lowermost edge of the wall, and the whole of the wall within these points removed. To facilitate removal, the white line should be grooved between the points b and d. After-treatment is exactly the same as that just referred to.

B. CORNS.

Definition.—In veterinary surgery the term 'corn' is used to indicate the changes following upon a bruise to that portion of the sensitive sole between the wall and the bar. Usually they occur in the fore-feet, and are there found more often in the inner than in the outer heel.

The changes are those depending upon the amount of haemorrhage and the accompanying inflammatory phenomena occasioned by the injury.

Thus, with the haemorrhage we get ecchymosis, and consequent red staining of the surrounding structures. As is the case with extravasations of blood elsewhere, the haemoglobin of the escaped corpuscles later undergoes a series of changes, giving rise to a succession of brown, blue, greenish and yellowish coloration.

With the inflammation thereby set up we get swelling of the surrounding bloodvessels, pain from the compression of the swollen structures within the non-yielding hoof, and moistness as a result of the inflammatory exudate.

In a severe case the inflammation is complicated by the presence of pus.

Classification.—Putting on one side the classification of Lafosse (natural and accidental), as perhaps wanting in correctness, seeing that all are accidental, and disregarding the suggested divisions of Zundel (corn of the sole and corn of the wall) as serving no practical use, we believe, with Girard, that it is better to classify corns according to the changes just described.

Following his system, we shall recognise three forms: (1) Dry, (2) moist, (3) suppurating.

The dry corn is one in which the injury has fortunately been unattended with excessive inflammatory changes, and where nothing but the coloration imparted to the horn by the extravasated blood remains to indicate what has happened.

The moist corn is that in which a great amount of inflammatory exudate is the most prominent symptom. It indicates an injury of comparatively recent infliction.

The suppurating corn, as the name indicates, is a corn in which the inflammatory changes are complicated by the presence of pus.

Causes.—The causes of corns we may consider under two headings—namely, predisposing and exciting.

Predisposing Causes.—By the heading of this chapter we have already intimated that corns are due to faulty conformation of the foot. It is, therefore, merely a description of such shapes of foot as favour their formation that will need mention here.

The wide, flat foot, with low heels, may be first considered. Here the posterior portions of the sole, those portions between the wall and the bars, fall very largely in the same plane as the wearing surface of the bars and the wall. As a consequence, these portions of the sole are more prone to receive injury from stones and rough roads and from the pressure of the shoe.

The low heels, too, favour a more than due proportion of the body-weight being thrown on to the posterior parts of the foot. Two evils, both inclining to the production of corn, result from this. In the first place, the sensitive structures of the posterior portions of the foot are subjected to undue pressure from above; secondly, the posterior half of the foot, by reason of the extra weight thrown upon it, is exposed also to greater effects of concussion than normally it should meet. Added to this we find that the abnormally flat condition of the sole has resulted in a great loss of resiliency. With undue pressure above, and a loss of resiliency and added effects of concussion below, the sensitive structures included between the opposing pedal-bone and the horny sole are bound to suffer more or less bruising each time the foot comes to the ground, especially if the animal is moved at a rapid pace.

Writing here of the effects of pressure and concussion affords a fitting occasion to mention the fact that corns occurring in feet affected with side-bones are always worse than in feet with normal elastic cartilages. The explanation of this is simple, for there can be no doubt that the loss of resiliency in the diseased cartilage is only another aid to undue pressure and concussion. The sensitive structures are pinched between unyielding bone above and practically unyielding horn below.

Feet with high and contracted heels are also predisposed to corn. The contraction in this case interferes with the downward movements of the os pedis during progression, while in a state of rest there is a more or less constant pressure upon the sensitive structures, due to the correct downward displacement of the pedal-bone being opposed by the amount of contraction present. In the contracted foot, too, the nutrition of the vessels supplying the secretory apparatus of the horn is largely interfered with. The horn loses its natural elasticity, fails to respond to the normal movements of the parts within, and aids in the compression and laceration of the sensitive structures.

Weak feet, with horn too thin to withstand the expansive movements continually going on—in other words, feet with weak, spreading heels—are also prone to suffer from corns. In this case the flatness induced by the spreading, and the insufficient protection afforded by the thin horn, both combine to lay the sole open to the effects of concussion and direct injury.

Brittle feet—feet with horn of undue dryness, by reason of the contraction thus brought about—are, again, particularly subject to corn.

So also with long feet. Whether occurring as a natural deformity, or as the result of insufficient paring, bruises of the sole in feet thus shaped are common. The reason for this will be better understood when we come to deal with the shoeing.

Other and minor predisposing causes are those mainly referring to an unnatural dryness of the hoof when animals reared in the country are put to work in large towns. We here really get several predisposing causes combining. A sudden change is made from a more or less moist condition underfoot to one excessively dry. The character of the travelling is wholly altered from occasional work upon soft lands to continual labour upon hard-paved roads. The horn is often exposed to the vicious influences of unsuitable litter, the application of unsuitable dressings, and the deleterious effects of the street mud of our cities. All these play their part in determining a condition of the horn, rendering it open to receive the effects of the more exciting causes which we shall next consider.

Exciting Causes.—Than the shoeing, no more frequent and exciting cause of corn exists. Whatever the predisposing influences may be, it is the shoeing that in nearly every case completes the list, and finally inflicts the injury.

The evils in this connection we shall consider under two headings—viz., (1) the manner in which the foot is pared; (2) the make and fitting of the shoe.

First among the faulty preparations of the foot comes that of excessive thinning of the sole, especially in the regions subject to corn. The farrier addicted to this is not as a rule content to confine his operations to the sole alone. In addition, the frog and the bars also suffer from the too lavish use of his knife. His main object is doubtless that of giving a broad and open appearance to the foot. It follows from this that his operations are confined more to the posterior than the anterior parts of the foot, and that the toe is therefore left too long. This gives us a combination of causes leading to pressure and bruises upon the sensitive structures at the seat of corn.

By this unequal paring of the toe and the heels greater weight is thrown upon the posterior half of the foot. What then happens to the structures thinned as we have described is this: the pared frog, lessened in volume, does not meet the ground. It therefore fails to expand laterally with weight, and cannot assist, as normally it should, in aiding the heels generally in their movements of expansion. The weakened bars and the thinned sole, meeting with no opposition from the frog, give downwards and inwards with the body-weight at the precise moment these movements should be directed mainly outwards. As a further result of non-resistance on the part of the frog, this time in a lateral direction, the bars, the sole, and the wall at the heels all contract at the exact time they should expand. The end result must mean abnormal pressure and bruising of the sensitive structures in that particular region. Naturally, also, the excessive thinning of the horn renders direct injury to the sole from stones or other objects in the road far more probable.

For this one reason alone—the manner in which it favours the production of corn—too great a condemnation cannot be placed upon excessive paring of the sole, the bars, and the frog.

When corns are already present, as they may be from other causes, the same remarks will again apply to excessive paring. It is the custom with many smiths to carefully pare down the discoloured horn in every case of corn they meet with, and at the same time to again weaken the bars and even part of the wall at the heels, with the laudable idea of relieving pressure on the part diseased. After what has gone before, we need hardly say that their well-meant efforts have a precisely opposite effect to the one they intend.

The fitting of the shoe is, perhaps, to a greater extent responsible for the causation of corn than is the paring we have just described.

A few of the evils connected with the shoe may, however, be justly described as unavoidable. We must shoe; we cannot shoe and leave a normal foot!

A shoe excessively seated, especially from the last nail-hole backwards, may be regarded as dangerous. In this case, with every application of the body-weight, there is given to the foot a tendency to contract, especially at its lower margin. Result: undue pressure upon the tissues around and the production of corn.

On the other hand, varying with the form of foot, the seating may be insufficient. In the case of flat-foot, or dropped sole, for instance, insufficient seating will lead to undue pressure of the web of the shoe upon the sole, and in that way bring about bruising of the sensitive sole beneath.

Shoes with heels or calks too high, by destroying the counter-pressure of the frog with the ground, serve to bring about a series of changes we have described under contraction, and again result in pinching and bruising of the sensitive structures.

The opposite excess—a shoe thick at the toe and thin at the heels—is blamed by Zundel for causing a like injury. In our opinion, the reason this author gives—namely, that the throwing of greater weight upon the heels leads to bruising of the sensitive structures—can only correctly apply to a wrongly-applied shoe of this type, and not to the shoe itself. True, a shoe with a thick toe and thinned heels will throw an undue proportion of the body-weight upon the heels if the foot is not properly prepared for it. A wise man, however, will most certainly so cut down the toe for the reception of this shoe that, with the shoe in position, there will still be maintained a tread that is normal. To our minds harm is far more likely to arise from a shoe of this class through the thinned iron heels of the shoe becoming attenuated under wear to the point of bending, and so inflicting an injury upon the adjoining sole.

Similarly, this last remark with regard to the thinning of the heels of the shoe will apply to a shoe with too broad a web. As the thinning of the shoe proceeds with wear, the inner portion of the thinned branch is bent up on to the sole, and again inflicts the injury.

The matter of bearing is also of importance when considering the causation of corn. In a previous chapter we have already described the correct bearing as that which includes the whole of the lower margin of the wall and the white line, and just impinges on the sole. Any marked deviation from that will, if long continued, be followed by injury to the foot.

With the bearing surface of the shoe too narrow—in contact with the wall solely, or perhaps only a portion of it—it is evident that a large proportion of the foot that should properly bear weight is thrown out of action. A heavy strain is imposed on the white line, and undue descent of the sole and contraction of the heels brought about. Again the result of this is compression and bruising of the tissues around the seat of corn.

With its bearing surface too wide, the shoe immediately exerts direct pressure upon the sole with every movement of the animal. The sole normally is not made to receive this, and harm is bound to result.

Among other ill-fitting shoes we may mention the one with branches too short, and the one with the extremities of the branches too pointed. In the first case, as wear of the shoe proceeds, the thinned end is far more likely to turn in under the seat of corn than is a shoe with branches of ordinarily correct length. It is evident in the second case that the pointed branch, when thinned, is a more dangerous agent than the branch which is nearer the square at its end.

The matter contained in the first half of the foregoing paragraph explains in a large measure the rarity of corns in the hind-feet. Here there is nothing to prevent a shoe with branches of full length being used. The correct bearing is thus maintained, even with a shoe excessively thinned with wear, and the liability to injury from it decreased. An exception is to be found in the case of a feather-edged shoe, such as is used to prevent cutting or brushing. The thinning by wear from above to below of the branch already purposely thinned from side to side leads to the formation of a thin and narrow piece of iron admirably calculated to bend over and injure the sole.

Even with a shoe of correct length, with a flat-bearing surface at the heels, and other conditions favourable to correct application, evil may still result from the shoe itself being made too narrow. As a result of this, the branch of each side is set too far under the foot, with consequent injury to the sole. This is, of course, sheer carelessness on the part of the smith. When practised, however, it is not easy of detection, as in all cases the foot is rasped down to cover what has been done. In other words, the foot is made to fit the shoe and not the shoe the foot.

Recognising this close fitting of the shoe as a cause, we are able to explain in some measure how it is that corns should occur with greater frequency in the inner than in the outer heel. There is no doubt that the inner branch of the shoe is nearly always fitted closer than is the outer. In the fore-foot it is also often shorter. Take these two evils and add to them the fact that the inner heel is called upon to bear more of the body-weight than is the outer, and the frequency of corns in the inner heel will no longer be wondered at.

Indirectly, the shoe may still be a cause of corn by reason of the irritation set up by gravel and small pieces of flint becoming firmly fixed between the sole and the web of the shoe. In nearly every case of this description the part to be injured is the white line.

Corns may also result from the animal picking up a stone. The stone becomes firmly wedged in between the inner border of the branch of the shoe and the bar or the frog. With every step the animal takes it becomes wedged more tightly into position. Projecting below the level of the lower surface of the shoe, it imparts the concussion it thus obtains directly to the sole. A bruise—and a bad bruise—is the result.

Finally, it cannot be denied that the work the horse is put to is largely responsible for the causation of corn. In country animals corns are comparatively rare, while in animals in town, almost constantly upon hard paving, they are common. This seems to point strongly to the fact that concussion through constant work upon unyielding roads is a great factor in their production.

Symptoms.—Unless the discoloration of the horn is accidentally discovered by the smith, the simple, dry corn may go undetected. The disturbance excited by it is so small, and the pain occasioned so slight, that the patient may offer no indication of its existence.

Ordinarily, however, the first symptom is that of pain. The animal goes feelingly with one or both feet, in some cases even showing decided lameness. The lameness, however, is in no way diagnostic, and the lesion itself must be discovered before an exact opinion can be pronounced.

As an aside, it is well to observe in this connection that a negative opinion as to the existence of corn should never be given unless the superficial layers of horn have first been removed with the knife.

When standing at rest the animal exhibits signs more or less common to all foot lamenesses. He 'points' the foot—in other words, the limb is slightly advanced, the fetlock partly flexed, and the heels from off the ground. When both feet are affected they are pointed alternately, and the animal often manifests his uneasiness by repeated pawing movements, and by scraping his bedding behind him.

Should the injury run on to suppuration, the lameness becomes most acute. The pawing movements become more pronounced, and there is evident disinclination on the part of the animal to place the foot squarely on the ground. One is then led to manipulate the foot. The hoof is hot to the touch. Percussion causes the animal to flinch, and to flinch particularly when that portion of the wall adjoining the corn is struck. Finally, exploration with the knife reveals the serious extent to which the injury has developed. In a neglected case of this description it is even possible to detect the presence of pus by the amount of swelling and fluctuating condition of the coronet. The suppurative process has advanced in the direction of least resistance, and is on the point of breaking through the tissues immediately above the horn.

Lameness due to corn is oftentimes intermittent. With a simple corn, dry or moist, this intermission is largely dependent on the degree of dryness of the hoof or the road, and also on the character of the road surface. With a neglected, suppurating corn, on the other hand, variation in the degree of lameness, in addition to depending on circumstances such as these, is dependent to a larger extent upon the changes occurring with the suppuration. In this case the time of greatest lameness is immediately before the pus gains outlet. Immediately after its exit at the coronet the animal will go almost sound. Soundness continues so long as the opening at the coronet remains clear. The tendency, however, is for the opening thus made to quickly close again. Pus again accumulates, lameness arises as before, and disappears again with the second discharge of the contents of the sinus now formed.

Pathological Anatomy.—When dealing with their classification we gave in outline the main pathological changes to be met with in corns. It now only remains to give the same matter in slightly greater detail.

In dry corn the changes we meet with are those accompanying blood extravasation. From excessive compression of the parts, or from the effects of direct injury, a portion of the sensitive sole has become lacerated. The escaping blood stains the surrounding soft tissues after the manner of blood extravasation elsewhere. If the escape of blood is sufficiently large, the horn fibres in the immediate vicinity also are stained. It is this stain in the horn that is the direct evidence of the injury, and is itself popularly known as the corn. It may vary in size from quite a small spot to a broad patch as large as half a crown, while its colour may be a uniform red, or a mottled red and white. The microscopic changes in this connection are illustrated in Fig. 99.



Ordinarily, this ecchymosis of the horny sole is due to injury of the sensitive sole immediately beneath it. It may, however, proceed from injury to the vessels of the laminae either of the bars or of the wall. In this case the ecchymosis of the horny sole may be explained by the fact that the escaped blood tends to gravitate to that position.

When the corn is of long standing, or is due to repeated injuries on the same spot, the horn adjacent to the lesion becomes hard and dry, and often abnormally brittle, simply on account of the inflammatory changes thus kept in continuation. This is often seen when attempts are made to pare out the corn with the knife.

Should the injury be seated in the sensitive laminae, then the brittle nature of the horn secreted by the injured tissues makes itself apparent by the appearance of cracks in the wall of the quarter. Why this should occur will be readily understood by a reference to Fig. 100.



It will here be seen that the injury to the keratogenous membrane has led to great interference with the secretion of horn from the sensitive laminae. As a result, the regularly leaf-like arrangement of the horny laminae has been largely broken up. Certain of the laminae are altogether wanting, while others are broken in their length and rendered incomplete. With this condition there is always more or less contraction of the quarter.

Microscopic examination of the structures involved in such a case reveals the fact that with the contraction is an alteration in the normal direction of the horny and sensitive laminae.

They become bent backward, and, instead of the regular and normal arrangement depicted in Fig. 32, show the distorted appearance given in Fig. 101.

From the appearances and characters of the blood-stain in the horny sole we are able to deduce evidence relative to the duration and nature of the injury.



When, for instance, the stain is not to be found in the superficial layers of the sole, but is only discoverable by deep paring, then the injury is a recent one.

Where the stain is met with in the superficial layers of horn, and is quickly pared out, then the injury has been inflicted some time before, and has not been repeated. When, as is sometimes the case, layers of horn that are stained are found alternated with layers that are healthy, then we have evidence that the cause of the corn, whatever it may be, is not in constant operation.

Similar indication of the age of the injury is also afforded by the colour of the lesion.

A stain that is deep red is proof that the injury is comparatively recent.

A distinct yellow or greenish tinge, on the other hand, is evidence that the injury is an old one.

In the Moist Corn we have, in addition to the blood extravasation, the outpouring of the inflammatory exudate. In the most superficial layer of the horn this may not be noticeable. As one cuts deeper into the sole with the knife, however, it will be found that the lower layers of horn are more or less infiltrated with the discharge. This gives to the horn a soft consistence, a yellow appearance, and a touch that is moist to the fingers.

With the accompanying inflammation the cells in the neighbourhood of the injury are enfeebled and their normal functions interfered with. We may thus expect a corresponding interference with the growth of horn. This is exactly what happens, and as one cuts deeper still into the horn a point is finally reached when a well-marked cavity is encountered. A pale yellow and usually watery exudate fills it. This cavity points out the exact spot where the force of the injury has been greatest, where death of certain cells of the keratogenous membrane has resulted, and where the natural formation of horn has for a time been suspended.

In the Suppurating Corn, as in moist corn, we have pathological changes due to the tissue reaction to the injury, plus the addition of pus organisms. Confined within the horny box we have a discharge that, by reason of the living and constantly multiplying elements it contains—the pus organisms—is always increasing in bulk. This must be at the expense of the softer structures of the foot. Accordingly, as the formation of pus increases, we get pressure upon and final gangrene of the sensitive sole and of the sensitive laminae of the bars and the wall. With no outlet below, the pus formation increases until finally it finds its way out of the hoof by emerging at the coronet.

This in some instances it may do by confining its necrotic influences solely to the sensitive laminae of the wall, in which case, if a dependent orifice is quickly made at the sole, the injury to the laminae is soon repaired by the healthy tissue remaining.

In other cases, however, the necrosis has spread deeper. Caries of the os pedis, of the lateral ligaments of the pedal-joint, or of the lateral cartilages, is a result. When this occurs the exuding discharge from the coronet becomes thinner and more putrescent, and its feel, when rubbed between the fingers, sometimes gritty with minute fragments of broken-up bone. Here, unless operative measures prevent it, necrosis soon spreads deeper still. The deeper portions of the os pedis become affected. The capsular ligament of the joint is penetrated by the suppurative process, and a condition of septic arthritis results. The cavity of the joint becomes more or less tensely distended, according to the amount of drainage present, which in this case is almost nil, with matter in a state of putrescence. As a consequence, the surrounding ligaments become softened and yield, and the articular surfaces displaced. The articular cartilages also suffer, become necrotic in patches, and frequently wholly destroyed. The end result is one of anchylosis of the joint and permanent lameness.

Prognosis.—With the ordinary dry corn a return to the normal may nearly always be looked for. Similarly, with moist corn, and even with careful treatment of the suppurating variety, the same favourable termination may be looked for and promised.

What cannot so safely be assured is that a relapse will not occur. In other words, the extent of the injury, no matter how serious, does not often offer anything that cannot be overcome by Nature and careful surgery; but the conformation of the animal does. A vicious predisposing conformation once there is there always, and although the injury resulting from it may easily give way to correct treatment, the same injury is bound to re-occur when the animal is again put to work.

Although with care suppurating corn, like other cases of suppuration within the hoof, may yield to treatment, the owner of the animal should, nevertheless, be warned that the condition is a serious one, especially should the joint become affected. It may so happen, as sometimes in fact it does, that the animal may die as a result of the infective fever so set up. From no surface in the body can absorption take place quicker than from the synovial membrane of a joint. So soon, therefore, as this membrane comes in contact with septic material, so soon does a severe septic fever make its appearance. The septic matter has gained the blood-stream, and the patient succumbs to septic poisoning.

Apart from death occurring naturally, the changes taking place in the joint in the shape of bony growths or of actual anchylosis may be so severe as to render the animal useless, and slaughter may have to be advised.

Treatment.—We have already said that by far the most active cause in the production of corn is the shoe. It follows from this that it is to the shoeing we must largely look for a successful means of their prevention, and that the treatment of corn in its most simple form is really a matter for the smith, and not for the veterinary surgeon.

The faults in connection with the shoeing we have mentioned fully when treating of the causes of corn. From those we learn that a shoe with a flat-bearing surface, or one moderately seated but flat at the heels, is the correct shoe for nearly all feet. The heels of the shoe should not be too high, should not be too short, and should be wide enough apart from each other to insure the wall of the foot obtaining a fair share of the bearing. Finally, even with the present method of shoeing, whenever it is possible to allow the frog to come to the ground, it should be encouraged to do so, and excessive paring either of the latter organ or of the bars or the sole should be strictly discountenanced. Where the sole is thin, or the frog wasted, use a leather sole or a rubber pad. With these precautions, corns may be prevented from occuring even in a foot with a predisposing conformation.

When corn is present, the first treatment usually adopted is that of 'paring it out.' This is advocated by Percival and by many other writers. We cannot say, however, that we agree with it—at any rate, not in the case of simple dry corn.

'Paring it out,' and by that we mean thinning down the sole until close on the sensitive structures, can only be advised in the case of suppurating corn, or in cases where doubt exists as to whether pus is present or not. In the latter case paring becomes necessary as an exploratory means to diagnosis.

When it appears fairly certain, even in the case of a moist corn, that pus does not exist, then paring is to be discountenanced, for the reason that it only tends to weakening of the parts and to assist largely in the corn's recurrence.

Those who advocate it do so for the reason that it relieves pressure on the injured parts.

That it does so directly from below cannot be denied; but that it also favours contraction and compression from side to side is equally certain.

A moderate paring may, however, be indulged in, say, to about one-half the estimated thickness of the sole. Softening of the horn and consequent lessening of pressure may then be brought about by the use of oil, oil and glycerine, tincture of creasote, or by poulticing.

In the case of a moist corn the paring should be stopped immediately the true nature of the injury has made itself apparent. Warm poultices or hot baths should then be used in order to soften the surrounding parts, lessen the pressure, and ease the pain. After a day or two day's poulticing, should pain still continue with any symptom of severity, the formation of pus may be expected, and it is then time for the paring to be carried further, until the question 'pus or no pus?' is definitely settled.

Should the moisture be due simply to the presence of the inflammatory exudate, then poulticing alone will have the desired effect, and the pain will be lessened. With the decrease in pain the poulticing may be discontinued, and the horn over the seat of the injury dressed with some antiseptic and hardening solution. Sulphate of zinc, a mixture of sulphate of zinc and lead acetate, sulphate of copper, or the mixture known as Villate's solution,[A] may either of them be used. Suitably shod, and with a leather sole for preference, the animal may then again be put to work.

[Footnote A: The composition of the escharotic liquid bearing his name was published by M. Villate in 1829 as under:

Subacetate of lead liquid ... ... ... 128 grammes. Sulphate of zinc [=a=a] ... ... ... 64 grammes. Sulphate of copper, [=a=a] ... ... ... 64 grammes. Acetic acid ... ... ... ... 1/2 litre.

Dissolve the salts in the acid, add little by little the subacetate of lead, and well shake the mixture.]

When dealing with suppurating corn, then, a considerable paring away of the horn of the sole becomes a matter of necessity. The freest possible exit should be given to the pus, and this even when an opening has already occurred at the coronet. Unless this is done, and done promptly, the putrescent matter still contained within the hoof will make further inroads upon the soft structures therein, and later upon the ligaments, and even bone itself.

Having given drainage to the lesion by the dependent orifice in the sole, poulticing should again be resorted to and maintained for at least three or four days. The poulticing may then be discontinued, and the openings in the sole injected with a weak solution of Tuson's spts. hydrarg. perchlor., a 1 in 20 solution of carbolic acid, a solution of copper sulphate, with Villate's solution, or with any other combined antiseptic and astringent. The success of the treatment is soon seen in the cessation of pain and in the decreased amount of discharge from the opening in the sole.

Should pain unfortunately continue, the discharge remain, and a state of fever reveal itself, then it may be understood that the suppurative process has not been checked, that a portion of necrosed ligament, cartilage, or bone still remains, which, surrounded as it is by pus organisms and putrefactive germs, is sufficient to excite a constant irritation and maintain the internal structures in a state of infection. In other words, we have what is known as a quittor.

This will call for deeper operation. The horn of the wall must be removed, and the diseased structures, whether gangrenous keratogenous membrane, necrosed ligament, or carious bone, carefully excised or curetted. This will be better understood by a reference to the chapter on Quittor, where the means for carrying out the necessary operative measures will be found described in detail.

Surgical Shoeing for Corn.—In the case of an ordinary dry corn, where the injury has been definitely ascertained to be accidental, no alteration in the shoeing will be necessary. Where, however, the corn is attended with a more than ordinary degree of inflammation, or where for some reason or other excessive paring has been practised, then it will become needful to shoe with a special shoe. The object to be attained is the removal of pressure from that portion of the wall next to the seat of corn.

The most simple shoe for effecting this is the ordinary three-quarter shoe. The only way in which this differs from the ordinary shoe is that about an inch and a half of that branch of the shoe adjoining the corn is cut off (Fig. 102). If at the same time contraction of the heels exists, then, perhaps, a better shoe is that known as the three-quarter bar (Fig. 103).

Or, if preferred, a complete bar shoe such as that described for sand-crack may be used, and the upper portion of the web in contact with the foot at the seat of corn thinned out so as to avoid pressure on the wall at this point. With this shoe we shall at the same time supply a certain amount of pressure to the frog, and aid in the healthy development of the part indirectly involved in the disease.

The same pressure may also be given to the frog, and protection afforded the sole, by the use of a leather sole, or rubber pad on leather, as described when dealing with contracted feet.

A further method of relieving pressure on this portion of the wall, without removing the wall itself (a practice which should never be advised) is to make certain alterations in the web of the shoe. This may be done in one of two ways.



In the first, that portion of the bearing surface of the heel of the shoe is 'dropped' about 1/8 inch from the plane of the remainder, so that the shoe at this position does not come into contact with the foot at all (see Fig. 104).

In the second case the shoe is what is termed 'set' at the heel. Here it is the plane of the wearing surface of the shoe that is altered. The hinder portion of the required heel is thinned so that its lower surface does not come into contact with the ground. By this means the wall is freed from concussion and pressure. At the same time the upper surface of the shoe is in contact with the wall of the foot (see Fig. 105).

This 'setting' of the shoe is preferable to the method first described. It affords a greater protection to the foot, and does not allow of fragments of stone and flint getting in between the foot and the shoe, and so giving rise to further mischief.

The 'set' portion should be fitted full and long. It is obvious, too, that the animal should not be allowed to carry the shoe too long; otherwise, as the other portion of the shoe wears down to the level of the 'set' heel, pressure on the tender part of the foot will again result.



In applying surgical shoes for corn of long standing, it must be remembered that the protection so afforded must be continued for some time. It is not sufficient to see the lesion itself disappear. In addition to that there is also, in the majority of cases, a certain amount of contraction to be overcome. This can only be done by continuing the use of a leather sole or some form of frog or bar-pad as recommended for the relief of that condition.

C. CHRONIC BRUISED SOLE.

A similar condition to that of corn may be met with in other positions on the sole. It is described by Rogerson as sand-crack of the sole[A], and is invariably met with around that portion of the sole in contact with the shoe.

[Footnote A: Veterinarian, vol. lxiii., p. 51.]

The animal is lame, and the shoe is removed in order to ascertain the cause. Nothing at first is noticeable except that the animal flinches when pressure is applied to the spot with the pincers, or the sole is tapped with the hammer.

On removing the sole with the knife, however, a distinct black mark is discovered, which, when followed up by careful paring, is often found to have pus at the bottom.

In this case the injury has resulted, as we have already intimated elsewhere, from causing the animal to wear for too long a time a shoe with too broad a web or insufficiently seated. Or it may have originated with the irritation set up by foreign and hard substances between the web of the shoe and the foot.

In his description of this condition Mr. Rogerson draws attention to the fact that the pus found should not be wrongly attributed to accidental pricking of the foot. He says:

'Considering that the cracks or splits are always found in the immediate vicinity of the nail-holes, a certain amount of discretionary skill is required in order that the lameness may be attributed to its proper cause. This is an instance in which the presence of the veterinary surgeon is imperative, in order to prevent undue blame being attached to the shoeing-smith. Misconception in these cases might very easily arise when parties concerned are disposed to accept an unskilled opinion, sometimes resulting in danger to the proprietor of the forge, not only of losing a shoeing contract, but also of being involved in other ways which would probably prove even more disastrous.

'Horses that stand on sawdust or moss litter are sometimes found with extensive discoloration of the horny sole in front of the frog. Their bedding material collects in the shoe as snow does, and forms a mass, which keeps a continued and uneven pressure upon the sole. A sound foot is not injuriously affected, but a very thin sole is, and so also is a sole which has been bruised by a picked up stone. Even a slight bruise becomes serious if pressure is allowed to remain active over the injured part. Lameness increases, serous fluid is effused between the horn and sensitive part, or even haemorrhage may take place.'[A]

[Footnote A: Hunting, Veterinary Record, vol. xiv., p. 593.]

The Treatment of Chronic Bruised Sole offers no special difficulty. Removal of the cause (in nearly every case incorrect bearing of the shoe) is the first consideration. That done, the lesion may be searched for and treated in the ordinary manner as described for corn. When pus is present it must, of course, be given exit, and an antiseptic solution applied to the wound. Should the sensitive structures be laid bare when allowing the pus to escape, then the wound so made should afterwards be protected with a leather sole and antiseptic stopping.



CHAPTER VIII

WOUNDS OF THE KERATOGENOUS MEMBRANE

A. NAIL-BOUND—BIND OR TIGHT-NAILING.

Definition.—By the term 'nail-bound' is indicated that accident occurring in the forge in which the nail of the shoe is driven too near the sensitive structures. Although involving no actual wound, it is important to consider the condition under the heading of this chapter, in order that it may be distinguished from the graver accident of a 'prick.'

Causes.—Very largely the whole matter of causation turns on the correct fitting of the shoe. The points especially to be noticed in this connection are (1) the position of the nail-holes in the web of the shoe, (2) the 'pitch' of the nail-holes.

Regarding the position of the nails, it goes without saying that the first consideration when 'holing' the shoe should be to punch the holes opposite to sound horn. This remark applies especially to shelly and brittle feet, the type of feet in which tight-nailing most often occurs. The next consideration in this connection is that of punching the holes so that the nail emerges from the upper surface of the web at exactly its correct point of entrance on the bearing surface of the foot. This should be on the white line immediately where it joins the wall. From this position any marked deviation inwards ('fine-nailing,' as it is termed) is bound to give to the nail a direction dangerously near the sensitive structures.

The 'pitch' of the nail-holes should be such that the nail is guided more or less nearly to follow the line of inclination of the wall. Accordingly, the nail-holes at the toe should be 'pitched' distinctly inwards, the inward pitch lessening as the quarters are reached, until the hindermost nail-hole or two is pitched in a direction that is almost perpendicular.

Too great an inward inclination of the nail will, however, give rise to a bind.

It is probable that 'tight-nailing' results more often from fine punching of the shoe than from any fault in the pitch of the hole. Inattention to either detail, however, is apt to bring the mischief about.

Even with a correctly fitted shoe, and with a normal foot, tight-nailing may occur as a result of sheer carelessness on the part of the smith.

Symptoms.—Possibly the animal returns from the forge sound. It is on the following day, as a rule, that evidence of the injury is given by the animal coming out from the stable lame. In a well-marked case the foot is warmer to the hand than its fellow, and percussion over the wall will sometimes reveal the particular nail that is the cause of the trouble. Should the shoe be removed, then the fact that the hole the nail has made is far too close to the sole often points out at once the seat of the mischief.

Treatment. As to whether or not the shoe should be removed is very much a matter for careful discretion on the part of the veterinary surgeon. Where the foot is shelly and brittle even a good smith sometimes finds himself unable to firmly attach the shoe without verging closely on causing the condition we are now describing. The author has known cases where animals with feet of this description have almost invariably returned from the forge, or rather been found the next day, with a suspicion of tenderness. After the lapse of a day or two this has quite often disappeared, and nothing in the meantime been done with the foot. Seeing, therefore, that removal and refitting of the shoe is in this case attended with risk of breaking away portions of the brittle horn, and so rendering the foot in an even worse condition than it was before, it is policy to decline to have the shoes removed unless worse symptoms make their appearance.

In coming to this decision the veterinary surgeon must be guided by noting in the wall the points of exit of the nails. Should the nail adjoining the position already pronounced to be tender have come out at a higher point than the others, it may be assumed that at a lower position in its course through the horn it has gone near the sensitive structures without actually penetrating the horny box, and that in the course of a day or two the sensitive structures involved will accommodate themselves to the pressure thus inflicted.

If, on the other hand, symptoms of tight-nailing show themselves in an animal with good sound feet, then there is no objection to be raised against having the shoe at once removed. Should the offending nail be definitely detected, then the shoe may again be put on, and that particular nail omitted from the set.

B. PUNCTURED FOOT.

(Pricked Foot—Nail-tread—Gathered Nail.)

Definition.—Under this heading we propose describing wounds of the foot occurring in the sole or in the frog, and penetrating the sensitive structures beneath.

Causes.—These we shall consider under two headings:

1. Wounds resulting from the animal himself 'picking-up' or 'treading' on the offending object.

2. Cases of pricking in the forge.

Those occurring under the first heading are, of course, purely accidental. In the majority of cases, the object picked up is a nail; but similar injury may result from the animal treading on sharp pieces of wood or iron, on pieces of umbrella wire, on pointed pieces of bones, broken-off stable-fork points, sharp pieces of flint, etc. The same accident may also occur in the forge as a result of the animal treading on the stumps of nails, from treading on an upturned shoe with the stumps of nails in situ, or from treading on an upturned toe-clip. It may also occur from an accidental prick with the stable-fork when 'bedding up,' or from casting part of a shoe when on the road and treading on the nails, in this case left sometimes partly in and partly out of the horn.

'Serious wounds of this description are also met with in animals engaged in carting timber from plantations in which brushwood has recently been cut down. This is, of course, from treading on the stake-like points that are left close to the ground. Hunters also meet with the same class of injury when passing through plantations or over hedge banks, where the hedge has just been laid low or cut down.

'Agricultural horses also meet with severe wounds of this class from treading on an upturned harrow.'[A]

[Footnote A: Journal of Comparative Pathology and Therapeutics, vol. iv., p. 2.]

It has been remarked how strange it is that nails should so readily penetrate the comparatively hard covering of the foot. The matter, however, admits of explanation. One knows from common observation how easy it is to tilt a nail with its point upwards by exerting a pressure in a more or less slanting direction upon its head. This is exactly the form of pressure that is no doubt put upon the nail if the animal treads upon it when moving at any pace out of a walk. The foot in its movement forward tilts the nail up, and almost simultaneously puts weight upon it. The great weight of the animal is then quite sufficient to account for its ready penetration.

In purely country districts cases of punctured foot are of far less frequent occurrence than in large towns. In the latter, animals labouring in yards where a quantity of packing is done, or engaged in carting refuse containing such objects as we have mentioned, or broken pieces of earthenware or glass bottles, meet with it constantly.

For the manner of causation of those wounds to the foot occurring in the forge the reader may be referred to the matter under the heading of 'nail-bound.' As in that case so in this the nail may be wrongly directed by improper fitting of the shoe, by the 'pitch' of the hole, or by the position of the hole. The nails may also be wrongly directed as a result of faulty pointing, or by meeting with the stump of a nail that has carelessly been allowed to remain in the substance of the horn.

Often pricking is a result of carelessness engendered by a rush of work. Often it is almost unavoidable on account of the character of the foot that is brought to be shod. Feet with thin horn, especially a thin sole, feet with horn shelly and brittle, each in their way are difficult to shoe.

Sometimes pricking is purely accidental, as in the case of a 'split' nail. The nail as it is driven splits at its point, and continues to split down its centre, one half emerging at the correct spot on the wall, the other half bending inwards, and penetrating the sensitive structures.

Common Situations of the Wound.—In a case of picked-up nail the common seat of puncture is about the point of the frog, either in one of the lateral lacunae, in the median lacuna, or the apex of the frog itself. In comparison with this puncture of the sole is rare.

Prick sustained at the hands of the smith may, of course, run in either of the following directions: (1) Directly into the position where the horny and sensitive laminae interleave; (2) between the sensitive laminae and the os pedis; (3) into the os pedis itself; (4) the nail may bend excessively immediately after entering the horn, and so pass either between the horny and sensitive sole; or (5) between the sensitive sole and the bone.

Classification.—Punctured wounds of the foot may be classified as follows:

Simple or superficial when penetrating no structure of great importance. For instance, a prick that penetrates to the sensitive sole and is not driven with sufficient force to seriously injure the os pedis we may regard as simple. In the same manner a prick to the frog that, although deep, is mainly concerned with penetrating the plantar cushion may also be classed as simple.

Deep or penetrating when driven with sufficient force or in such a direction as to injure structures whose penetration is calculated to give rise either to serious constitutional disturbance or to permanent lameness. In this category we may place injuries to the terminal portion of the perforans, puncture of the navicular bursa, fracture of the navicular bone and penetration of the pedal articulation, and splintering of the os pedis.

Symptoms and Diagnosis.—While discussing the symptoms and diagnosis, we will still continue to consider our subject under the two headings of (1) accidental 'gathering' of some foreign body, and (2) pricks inflicted in the forge.

In a few cases belonging to the former class the veterinary surgeon is fortunate in obtaining a direct history of the injury. The driver has seen the animal go suddenly lame, and has examined the foot for the cause. Either the nail has been found embedded in the horn, or the puncture it has made detected, and the matter has been reported. The foot is then explored and the full extent of the injury ascertained.

In many cases, however, it so happens that no evidence of the infliction of the injury is forthcoming. The momentary lameness occurring at the time of the prick is unreported at the time by the attendant, and the horse for a time goes sound. It is not until the changes set up by the subsequent inflammatory phenomena make their appearance, and lameness results, that attention is called to the foot. When this happens there has, as a rule, been time for pus to form around the seat of puncture—a matter of about forty-eight hours.

The horse is now brought out for the veterinary surgeon's examination, going distinctly lame. If the case is well marked there may then be noted by the man of experience many little signs pointing to the foot as the seat of the lameness. These, though well enough known to the practitioner, are nevertheless difficult to describe. It is, in fact, hard to say exactly in what they really consist, appearing to be as much a matter of intuition as of actual observation.

There is a peculiar 'feeling' characteristic in the gait. The affected foot is put forward fearlessly enough, but is not nearly so rapidly put to the ground. When at rest the foot is almost immediately pointed, and the pain at intervals manifested by pawing movements. It is this extreme liberty of the rest of the limb, as evinced during the pawing movements, that really strikes one. Shoulder, elbow, knee, and fetlock are all easily and painlessly flexed and extended. There is nothing wrong with them; it must be the foot. The short manipulation necessary to test the lameness—viz., the walk and slow trot—is sufficient to raise the animal's pulse and quicken the breathing.

All this is enough, and more than enough, to lead the veterinary surgeon to examine the foot. It is hot to the touch, and at the coronet tender to pressure, possibly in a neglected case fluctuating at the heel. Pain is evinced by the animal withdrawing his foot when percussion takes place over the affected spot. In a bad case one gentle tap is all that is needed. The animal at once snatches away his foot, holds it high from the ground, and makes pawing movements in the air. At that moment, too, his countenance is highly expressive of the pain he is suffering. Again the foot is explored, the injury found, and the pus liberated.

Regarding the manner of exploration of the foot we will take first that case in which the veterinary surgeon is called in early, and in which pus has not yet had time to form. Sometimes the merest cleaning up of the inferior surface of the foot then reveals a distinct stab either in the sole or the frog.

If the accident be recent only a little blood will be found, either liquid, or coagulated about the wound. Later there exudes from the stab a flow of yellow, serous fluid. The opening thus found should be carefully probed, and its depth and situation noted.

At other times the prick is not so readily apparent. The nail or other object has penetrated and afterwards withdrawn itself. The natural elasticity of the horn, especially that of the frog, causes it to contract upon the puncture, and to largely obliterate the hole made. What, therefore, may look to be but a simple injury to the horn alone may in reality be the only evidence of a stab complicating the sensitive structures. It thus behoves the veterinary surgeon to follow up and carefully cut out any unnatural-looking mark in the horn, more especially if the horn is discoloured, or if blood is extravasated into its fibres, or there is moisture exuding from the part.

In some cases of this description the knife in the act of paring comes into contact with the cause of the trouble. Sometimes this is a nail, sometimes a sharp and small piece of flint, so deeply penetrated as to have become quite buried. When met with in this manner, however, the foreign body is more often than not a splinter of wood deeply embedded in the cleft of the frog or in the frog itself.

The fact that multiple punctures may occur should here be remembered, and the remainder of the inferior surface of the foot thinly pared.

On withdrawal of the foreign object blood may immediately follow. Should the former have been fixed in position for some time, however, pus is nearly always found at the bottom of the wound. As a rule, its removal is comparatively easy, but one case recalls itself to the author's mind in which the extraction was a matter of considerable difficulty. The offending object was a large, flat-headed nail, some 2 inches long. This was driven fast into the os pedis, and necessitated the employment of a pair of pincers and the exertion of some amount of force to move it from its position.

In this connection it must be remembered that the penetrating object sometimes breaks off after entering the foot. The fact that this occasionally happens only serves to give point to the advice we have previously rendered—that every stab should be carefully probed, and its exact condition and depth ascertained.

In those cases where percussion has led to the positive opinion that pus really exists, then the exploration must be most searching. There may, or may not, be a suspicious-looking mark to work on. In the latter case, the veterinary surgeon must not be content with confining his paring operations to one spot. The sole should be carefully thinned all round, and the thinning cautiously proceeded with until either small, pin-point haemorrhages denote that healthy sensitive structures have been reached, or a sudden flow of pus indicates that the injury has been definitely located.

While the symptoms remain much about the same, the diagnosis of pricks received in the forge, as compared with those occurring in the natural manner, is easy. The animal starts to the forge quite sound, and returns, perhaps, with a slight limp. The slight limp in two days' time becomes a decided lameness, and no doubt remains as to what has occurred. The mere fact of the lameness arising immediately after a visit to the forge should be sufficient in the majority of cases to lead one to a correct diagnosis.

Where the opinion has been formed that a prick has been received, then the shoe should be removed.

This operation should always be superintended by the veterinary surgeon himself. After the removal of the clinches, the nails should be drawn one at a time with the pincers, and carefully examined. Often the offending nail may thus be picked out by observing upon it blood-stains, or the moisture from inflammatory exudate or from pus. Further inflammation will also be gathered by occasionally meeting with a nail that has split.

At this stage, too, the veterinary surgeon should have noticed whether or not the smith has previously sent the animal home with what is known as a 'draw back.' He has discovered, immediately after he has done it, that he has pricked the animal. He has then withdrawn the nail, and either sent the animal back with that nail altogether missing from the set in the shoe, or with the hole filled up with a stump.

The shoe once off, the holes made by the nails in the horn should be minutely examined for the presence of haemorrhage, inflammatory fluid, or pus exuding from them, and also for evidence of their correct placing in the foot. Should fluid matter issue from any one of them, or should it be deemed that one has approached too near the inner margin of the white line, more especially if tenderness exists around it, that hole should be followed up with a 'searcher' or small drawing-knife until diagnosis is certain.

Complications.—Before proceeding to discuss the complications that may arise in the case of pricked foot, we may call to mind that the anatomy of the parts teaches us that the most serious position in which a punctured wound can occur is at the centre of the foot. Here the plantar aponeurosis, the navicular bursa, the navicular bone itself, or the pedal articulation may be injured.

Anterior to this position the most serious mischief that can ordinarily result is stabbing of the os pedis.

Posterior to the position we have named, the only structure to be injured is the plantar cushion.

Anatomically, then, the inferior surface of the foot may be divided into three zones, as follows:

A. Anterior, extending from the toe to the point of the frog.

B. Middle, extending from the point of the frog to the commencement of its median lacuna.

C. Posterior, including everything posterior to the middle zone.

This division of the inferior surface of the foot into zones will be somewhat of a guide also when describing the complications next to follow:

(a) Suppuration.—This is the common complication of most wounds of the foot. When detected, it calls for immediate surgical interference in the shape of removal of the horn of the sole or the frog, as the case may be. This we shall consider further under the treatment.

(b) Separation of the Horny Frog.—This is a sequel to pus formation in the sensitive structures immediately beneath it, and the condition makes itself apparent by a line of separation between the horn and the skin of the heel of the injured side.

(c) Wounding of the Plantar Aponeurosis.—This occurs when a moderately-deep penetration of the horn of the middle zone has taken place. It is always most painful, especially when complicated by necrosis. The heel is then persistently elevated, and lameness is extreme, in some cases so severe as to cause the leg to be carried altogether.

In favourable cases the necrosed piece of tendon is sloughed off by the process of suppuration, and escapes with the discharges from the wound. There is then an abatement in the symptoms, and recovery is rapid.

Commonly, however, on account of the non-vascularity of the structure of the tendon, the necrotic spot in it tends to spread. The wound is thus led to become fistulous in character, and the pus forming within it prevented from escaping from the original opening. As a result, lameness and fever persist. There is a gradual increase in the severity of the symptoms, and later fistulous openings appear in the hollow of the heel.

(d) Puncture of the Navicular Bursa.—This results from a prick in exactly the same position as that last described, and means that the penetrating object has gone deeper, It may be distinguished from puncture of the plantar aponeurosis alone by the fact that there is an excessive discharge of synovia from the wound. This, as it escapes, is at first clear and straw-coloured. Later it becomes cloudy and flaked with pus, and shows a tendency to coagulate in yellowish clots.

Pain and accompanying fever is most marked, much more so than when the plantar aponeurosis alone is injured.

Should the original wound be insufficiently enlarged, or should its opening become occluded by the solid matters of the discharge, then this condition, like the last, ends in the formation of fistulous openings in the heel. These make their appearance as hot, painful, and fluctuating swellings in that position. Later they break, discharge their contents, and leave a fistulous track behind.

(e) Fracture of the Navicular Bone.—Penetration of the substance of the navicular bone, without its fracture, adds nothing to the symptoms we have described under puncture of the bursa. That the bone has been reached by the penetrating object may be detected by probing. This, however, must be performed with care, especially if a flow of synovia is absent. Otherwise, the wound, as yet, perhaps, superficial enough to avoid penetrating even the bursa, is made a penetrating one by the probe itself.

Fracture of the navicular bone is fortunately rare.

(f) Penetration of the Pedal Articulation and Arthritis.—This we shall consider in greater detail in Chapter XII. It is sufficient here to state that the condition may be suspected when a hot and painful swelling of the whole coronet makes its appearance. There is at the same time a diffused oedema of the fetlock and the region of the cannon, sometimes extending upwards to the whole of the limb.

Of all the complications to be met with in punctured foot this is the one most to be dreaded. The intense pain and the high fever render the animal weak and thin in the extreme. The appetite becomes impaired, sometimes altogether lost, and the patient in many cases appears to die from sheer exhaustion. Added to this is always the extreme probability of the wound becoming purulent, and later the dread of general septic infection of the blood-stream ensuing, and death resulting from that. Even with the happier ending of resolution, anchylosis of the joint and incurable lameness is more often than not left behind. (See Suppurative or Purulent Arthritis, Chapter XII.)

(g) Ostitis and Caries of the Os Pedis.—Injuries to the os pedis are met with in the anterior zone of the foot. Evidence that the bone has been injured is not usually forthcoming until after the lapse of some days. One is led to suspect it by the fact that there is no indication of the suppurative process extending further upwards, coupled with the facts that great pain, high fever, and extreme lameness persist, and that there is a continuous discharge from the wound of a copious blood-stained and foetid pus. Used now, the probe reveals the fact that the bone is bared, and conveys to the hand that is holding it a sensation of crumbling fragility.

(h) Wounding of the Lateral Cartilage and Quittor.—This occurs as the result of a deep stab in the posterior zone. Ordinarily, wounds in this position are unattended with serious consequences, and the prick has to be a deep and a severe one before the cartilage is reached. What then happens is that a spot of necrosis is formed round the seat of puncture in the cartilage. This, unless met with surgical interference, is sufficient to maintain the wound in a septic condition; it takes on a fistulous character, and a quittor is formed. (See Chapter X.)

(i) Septic Infection of the Limb.—This we have already once or twice referred to. It simply means that the septic matters from the wound have gained the lymphatics, and finally the blood-vessels of the limb, and set up local lesions elsewhere than in the foot. Although dismissed here with these few words, the condition is a most serious one. Usually, it has resulted from penetration of the pedal articulation and septic infection of the joint. In the vast majority of these cases slaughter is both humane and economical.

Prognosis.—The first consideration in giving a prognosis in punctured foot should be the position of the wound. When occurring in the middle zone, the surgeon's statements should be most guarded, and the dangers attending a wound in that particular position fully explained to the owner. A wound in the anterior position is, as we have said, far less serious, and one in the posterior region of the foot even less serious still.

Whenever possible, the nail or other object causing the prick should be examined. Much of the prognosis may be based upon the estimated depth of the wound, and this, in many cases, it is far safer to calculate from the length of the offending body than from the use of the probe. We need hardly say that in the middle zone the deeper the prick, the more serious the case, and the less favourable the prognosis. As in succession the sensitive sole, the plantar aponeurosis, the navicular bursa, the navicular bone, or the pedal articulation is injured, so with each step deeper of the prick is the severity of the case increased.

The shape of the penetrating object may also be considered. One excessively blunt, and calculated to bruise and crush the tissues, will inflict a more serious wound than one of equal length that is pointed and sharp.

The conformation of the foot should also be regarded. Wounds in well-shaped feet are less serious than in feet with soles that are flat or convex, or in which the horn is pumiced or otherwise deteriorated in quality.

Although unaffecting the prognosis so far as the actual termination of the case is concerned, it may be mentioned that punctured foot is far more serious in a nag than in a heavy draught animal. With an equal degree of lameness resulting in each case, the former will be well-nigh useless, but the latter still capable of performing much of his usual labour.

The temperament and condition of the patient will also in many cases largely influence the prognosis. An animal of excitable and nervous disposition is far more likely to succumb to the effects of pain and exhaustion than the horse of a more lymphatic type. In the case of a patient suffering from a prick to a hind-foot while heavily pregnant, the attempted forecast of the termination should be cautious. More especially does this apply to the case of a heavy cart-mare. Ordinarily, the heavier the breed, the greater the tendency to lymphatic swelling of the hind-limbs. With pregnancy this tendency is enormously increased, and it is no uncommon thing to find a cart-mare in this condition, with legs, as the owner terms it, 'as thick as gate-posts.' A prick to the foot, with the lymphatics of the limb in this state, is extremely likely to end in septic infection of the leg, for there appears to be no doubt but that invasion of the lymphatics with septic matter is favoured by a sluggish stream. Also, in the case of a patient in the advanced stages of pregnancy, it must be remembered that, no matter how great may be the need, one is debarred, for obvious reasons, from using the slings.

Treatment.—In a simple case—and by 'simple' here we mean the case in which the injury is discovered early, and pus has not yet commenced to form—our first duties are to give the wound free drainage, and to maintain it in an aseptic condition. The first of these objects is to be arrived at by paring down the horn in a funnel-shaped fashion over the seat of the prick. It is, perhaps, even better to thin the horn down to the sensitive structures for some little distance round the injury. By this latter method pressure from inflammatory exudate is lessened, and the after-formation of pus, if unfortunate enough to occur, the more readily detected, and the less likely to spread upwards. The matter of asepsis may then be attended to.

When the puncture is sufficiently large to admit of it, the antiseptic dressing is best applied by means of the probe. This instrument is thinly wrapped with tow, or other absorbent material, so as to form a small swab. Dipped in a suitable solution (as, for example, Zinc Chloride, Spts. Hydrarg. Perchlor., Carbolic Acid, or any other that suggests itself), the swab is inserted into the prick, and the wound conveniently mopped clean. A further portion of the medicated tow is then pushed partially into the wound, and allowed to remain in position. The foot is subsequently wrapped in a clean bag, and kept free from dirt. This dressing should be repeated twice daily.

If the prick is in a dangerous position, and deep enough to occasion alarm, our precautions to prevent the formation of septic matters within it may be more elaborate. The thinning of the horn and the swabbing of the wound may, as before, be proceeded with. In addition, the whole foot may then be immersed for some hours daily in a cold bath, which bath should be strongly impregnated with one or other of the following salts: Iron Sulphate, Zinc Sulphate, Copper Sulphate, Aluminium Sulphate, Lead Acetate, or Sodium Chloride—better still, a mixture of the various sulphates here mentioned. If preferred, one of the more commonly accepted antiseptics—such as Carbolic Acid, Lysol, Boracic Acid, or Perchloride of Mercury—may be substituted.

By the cold of the bath inflammatory phenomena are held in check, while its added antiseptic prevents the formation of septic discharges. The lameness gradually diminishes, and resolution is rapid. In this way deep and serious, wounds are sometimes easily and successfully treated.

When suppuration has occurred—and this, by-the-by, is by far the most frequent condition in which we find punctured foot—treatment must be prompt and decided. Careful search must at once be made by thinning down the sole, and carefully trimming the frog. On no account should the veterinary attendant rest content with 'digging' in one place, and upon that basing a negative opinion as to the existence of pus. The paring should be carried on, until either pus or haemorrhage shows itself, in at least three positions—namely, at the most anterior portion of the sole, and in the sole at each side of the frog. In addition to this, the frog itself should be minutely examined for evidence of puncture, or for leaking of pus at the spot where the horn of the heels joins the skin.

In many of our cases, however, this careful search is not so necessary. The accompanying symptoms are so decided as to leave no doubt as to the condition of the case. In such instances paring may often be commenced over the exact position of suppuration as previously ascertained by percussion.

When met with, the track formed by the suppurative process should be followed up in whichever direction it has spread. This will often necessitate the removal of the greater part, if not the whole, of the horny sole.

Having given vent to the pus, and opened up the cavity made by its formation, the foot should be placed in a hot poultice or, preferably, in a hot antiseptic bath.[A]

[Footnote A: At the time of writing this, a certain amount of discussion is going on in our veterinary journals as to whether a hot or a cold bath is the one indicated. It is urged against the application of heat that it favours organismal growth and reproduction, and tends rather to induce the spread of the suppurative process than to overcome it. Those who hold this opinion urge in support of it that cold applications are inimical to the life of the pus organism. At the same time, it must be remembered that in just so far as cold inhibits the growth of the invading germ, so in just the same degree does it adversely influence the functions of the tissues that are to fight against it. To our minds the question thus set up must always remain more or less a moot-point, and while we fully agree that cold undoubtedly checks the growth of septic material, we just as fully believe that warmth serves to place the healthy surrounding structures in a far better condition to maintain a vigorous phagocytosis against it. We thus continue to advise a hot antiseptic poultice, or, better still, a bath.—THE AUTHOR.]

At the end of the third or fourth day the poultice or the bath may be discontinued, and the opening in the sole dressed with any suitable astringent and antiseptic.

The most serious complication arising from this method of treatment is one of excessive granulation of the sensitive sole. This we find to be successfully held in check by a daily application of undiluted Spts. Hydrarg. Perchlor. (Tuson). Should the granulations become very exuberant, then the knife must be called to our aid, and the wound so made afterwards dressed with an astringent.

When the suppuration has under-run the horny frog there should be no hesitation in at once removing all the horn that is visibly separated from the sensitive structures beneath.

When the os pedis is splintered and carious, a portion of the sole round the wound is removed, and the bone exposed. The diseased portion is scraped away either with a curette or with the point of the drawing-knife. In this case the only after-treatment called for is the application of suitable antiseptic dressings.

When necrosis of the plantar aponeurosis has occurred. We have already pointed out the tendency there is in this case for the wound to maintain a fistulous character, and lead to the formation of abscesses in the hollow of the heel. With a wound in this position, as with a wound in any other, the only method of avoiding this termination consists in removing all that is visibly diseased, whether it be soft structures, bone, ligament, or tendon, and giving the wound free drainage.

This can only be done by removing the horny sole and frog, and cutting boldly down upon the structures beneath. The operation is known as resection of the plantar aponeurosis, or the complete operation for gathered nail.

Practised for some years on the Continent, this operation, on account of its gravity, has been avoided by English veterinarians. From reported cases, however, it appears often to be followed by success.

That there is a large element of risk in the operation is quite evident, if only from the two facts mentioned beneath:

1. That the close attachment of the plantar aponeurosis to the navicular bursa, and the nearness of both to the pedal articulation, render penetration of a synovial sac or a joint cavity extremely likely.

2. That there is always great difficulty in maintaining strict asepsis of the foot, more especially if it is a hind one.

On the other hand, it may be argued that equal risk to the patient is run in allowing him to remain with a disease (and that disease a progressive one) of the structures so closely antiguous to the navicular bursa and the pedal articulation.

If only for that reason we give the operation brief mention here.

The animal is prepared in the usual way for the operating bed; the foot soaked for a day or two previously in a strong antiseptic solution, the patient cast and chloroformed, and the operation proceeded with.



An Esmarch's bandage should be first applied, and a tourniquet afterwards placed higher up on the limb. The foot is then secured as described in an earlier chapter, and the whole of the horny structures of the lower surface of the foot (the sole, the frog, and the bars) pared until quite near the sensitive structures, or, if under-run with pus, stripped off entirely. An incision is then made in each lateral lacuna of the frog, the two meeting at the frog's point. Each incision thus made should be carried deep enough to cut through the substance of the plantar cushion. A tape is then passed through the point of the frog, tied in a loop, and given to an assistant to draw backwards. The plantar cushion itself is then incised in a direction from before backwards, and pulled on by the assistant, so as to expose the plantar aponeurosis.

Should this be found at all necrotic, it may be taken that purulent inflammation of the navicular bursa and of the navicular bone itself exists. The operator must then proceed to resection of the tendon in order to treat the deeper structures thus affected. At its point of insertion into the semilunar crest the tendon is severed and afterwards reflected. This exposes the inferior face of the navicular bone. Instead of the glistening and clear appearance it ordinarily presents, its glenoid cartilage is found to be showing haemorrhagic or even purulent spots of necrosis. The terminal portion of the tendon must then be excised.

To effect this a clean transverse incision is made at the extreme upper border of the navicular bone. Here we are in close contact with the pedal articulation, and great care is necessary in making this last incision, in order that the synovial sac may not be penetrated.

All structures showing spots of necrosis should now be carefully removed, either with the knife or with the curette. The knives most suitable for the last stages of this operation are those depicted in Fig. 45 (c, d, and e). The curette, or Volkmann's spoon, we show in Fig. 106.



When at all diseased the glenoidal surface of the navicular bone should be curetted, even to the extent of the removal of the whole of the cartilage. A healthy, granulating surface is thus insured.

The above figure from Gutenacker's 'Hufkrankheiten' explains shortly the position of the operation wound and the structures involved, rendering further description unnecessary here.

The operation ended, the dressing follows. Upon this depends very largely the ultimate recovery of the patient, for it is only by careful attention and suitable dressings that effectual repair of the injured structures may be brought about.

A light shoe is first tacked on to the foot, and those portions of the horny sole that have been allowed to remain dressed with Venice turpentine, tar, or other thickly-adherent antiseptic.

The exposed soft tissues are then dressed with pledgets of tow[A] soaked in alcohol and carbolic acid. This dressing must be allowed to remain in position, and is kept there by means of a bandage, or the shoe with plates (Fig. 55) and a bandage over it. No pressure is needed; consequently, the pledgets of tow must not be too thick.

[Footnote A: When using tow in the form of a pad, it is well to remember that many small balls of the material rolled lightly in the palm of the hand and afterwards massed together are far better than one large pad of the tow taken without this preparation. The irregularities of the wound are better fitted, and the whole dressing easier remains in situ (H.C.R.).]

In the after-dressing of the wound careful attention must be paid to the granulating surface. Where tending to become too vigorous in growth it should be held in check by suitable caustic dressings. At the same time it must be remembered that the granulating process of repair is always more rapid upon the plantar cushion and fleshy sole than upon the bone, or upon tendinous or cartilaginous structures. As a result of this we have a wound showing various aspects of cicatrization. Healthy granulation may be profuse in one spot, while in another it may be checked either by a flow of synovia from the still open bursa, or by fragments of bone or of tendon still acting as foreign bodies in the wound. These latter may be readily detected by their standing out as dark and uncovered spots in the healthy granulation around, and should be at once removed.

The time that an operation wound of this description takes to heal—and that without complication—is from one to two or three months. Continuation of pain and intensity of lameness are not to be taken as indications of failure. The reparative inflammation in the synovial membrane is quite sufficient to induce pain severe enough to prevent the animal from placing his foot to the ground for some weeks, even though the progress of the case, all unknown, may be all that is desired. So long as a great amount of pain is absent, and so long as appetite remains and swellings in the hollow of the heel fail to make their appearance, so long may the progress of the case be deemed satisfactory.

Recorded Case of the Treatment.—A cart-horse, aged six years, was sent to the Alfort School by a veterinary surgeon for having picked up a nail in the hind-foot. Professor Cadiot, judging the necessity for the complete operation, performed it on January 14, and spared the plantar cushion as much as possible. In consequence of the plantar aponeurosis being extensively necrosed, it was advisable to scrape the navicular bone and a part of the semilunar crest. The wound having been washed with a 1 per cent. solution of perchloride of mercury, it was dusted with iodoform and packed with gauze, and covered with a cotton-wool dressing, kept in position by means of a suitable shoe.

On January 16 there was no snatching up of the limb when the horse was made to put weight upon it; he ate his food well, and his condition improved every day. On January 21 the dressing was removed; the wound appeared pinky and granular, and there was no suppuration. The clot remaining from the haemorrhage after the operation was removed, the wound was irrigated with a hot solution of sublimate, and then dusted with iodoform and covered with a dressing of iodoform gauze and absorbent wool. At this date the horse could stand on the injured limb. On January 31 a second dressing was made, and the animal almost walked sound. On February 7 the wound had almost closed up, save in its central part, where there was a small cavity, and the lameness had disappeared. On February 15 the wound had completely healed, and its borders were covered by a layer of thin horn. As the animal was sound it was sent to work.

The author directs attention to the rapidity with which a large and complete wound cicatrizes after the operation for gathered nail.[A]

[Footnote A: Veterinary Record, vol. XV., p. 226 (Jourdan).]

In the case of Penetrated Navicular Bursa, unaccompanied by the formation of any large quantity of pus, and uncomplicated by necrosis of the aponeurosis, our aim must be to maintain the wound in that happy condition. This is doubtless best done by keeping the foot continually in a cold bath, rendered strongly antiseptic by the addition of sulphate of copper and perchloride of mercury. Should there be intervals when the bath must be neglected, the foot in the meantime must be kept clean by antiseptic packing and bandaging, and a clean bag over all. This treatment should be continued so long as the character of the discharge denotes that synovia is running. If, in spite of our precautions, the discharge becomes purulent, then the track made by the penetrating object should be syringed twice daily with a 1 in 1,000 solution of perchloride of mercury.

During the treatment it will be wise to shoe the animal with a high-heeled shoe. We do not know as yet the full extent of the injury. The navicular bone may be tending to caries; or necrosis of the plantar aponeurosis, all unknown, gradually becoming pronounced. This calls for a relief of tension on the perforans, and is only to be brought about by the high-heeled shoe.