A Text-Book of Horseshoeing

Part 6B

by A. Lungwitz and John W. Adams Copyright 1897

CHAPTER VIII.

INFLAMMATIONS OF THE PODODERM (PODODERMATITIS).

1. Nailing.

Wounds of the velvety tissue of the sole or of the podophyllous tissue of the wall, caused by nails which have been driven into the hoof for the purpose of fastening the shoe, are usually termed “nailing.”

We distinguish direct and indirect nailing; the former is noticed immediately, the latter later.

In direct nailing the nail passes directly into the pododerm (velvety tissue of the sole, podophyllous tissue); the wound produced may vary from a simple puncture of the pododerm to chipping of the border of the os pedis, and is always accompanied by bleeding, even though it may not always be noticed.

In indirect nailing the nail does not pass entirely through the horn capsule, but very close to the sensitive tissues, and crowds the soft horn inward against them. This inward bulging presses upon the pododerm and causes inflammation and lameness, which may not manifest themselves for several days.

Symptoms. — The first symptom of direct nailing is instant pain indicated by flinching or a jerking of the limb, showing that the nail has taken a wrong course, and then a more or less profuse hemorrhage. Usually the blood flows from the nail-hole, or the nail when withdrawn may merely show a bloodstain at its point; however, internal bleeding may occur without any external manifestations. The symptoms of indirect nailing are entirely different. In this case pain does not arise immediately, but later, sometimes as soon as the horse attempts to bear his weight upon the shod foot. In the latter case, on holding up the opposite foot the animal sways backward and throws his weight upon the holder, or becomes restless. As a rule, the consequences of indirect nailing are first manifested after two or three days, infrequently from the eighth to the fourteenth day, as inflammation within the hoof and lameness, at which time a careful examination will usually reveal increased warmth of the hoof, pain upon pressure with the hoof-testers and on tapping the hoof lightly, some swelling of the entire foot, increased pulsation of the digital arteries, and unwillingness of the animal to place all or perhaps any of its weight upon the foot.

Suspicion of nailing should be entertained if the shoeing be recent, the hoof appear too small in relation to the body-weight, the walls have been thinned by rasping or have been broken away, or if the nails have been driven too high or very irregularly.

Causes. — The most common causes are mistakes in shoeing. In the majority of cases the cause is a disregard of the rule that the nails should penetrate the white line. 1, Using badly-punched shoes; 2, excessive paring and shortening of the hoof; 3, weakening of the lower border of the wall by excessive rasping away of the outside (Fig. 187, c); 4, mistakes in fitting the shoe, especially applying shoes that are too narrow, letting the toe-clips too deep into the horn, by which the nail-holes near the toe, instead of falling upon the white line, are carried back upon the edge of the sole, or using shoes in which the nail-holes are too wide or improperly directed; 5, using nails that are split, incomplete, badly formed and beveled, and too large; 6, starting nails too deep or with the bevel on the outside, or drawing them too tight. As occasional causes may be mentioned: 7, old nail-stubs in the horn; 8, walls that are very thin or broken away; 9, a soft, crumbling wall, which alters the sound and feeling of the nail as it is driven, and makes it difficult to judge of its course; 10, restlessness of the animal while being shod.

Examination. — Press with the hoof-testers upon the sole and clinches; tap lightly upon the clinches. If these acts cause pain, there can be little doubt that the nail is responsible for the damage. Remove the shoe by drawing each nail separately and carefully. Examine the nails with reference to their direction and size, as well as to staining with blood, blood-serum, or pus. Immediately after removing the shoe, look for the point of entrance of each nail into the hoof, and if a nail-hole be found upon the edge of the sole (Fig. 187, b) instead of in the white line, it is highly probable that the nail which passed in at that place pressed upon the sensitive tissues of the foot. Every nail-hole should then be searched by passing a clean new nail into it and pressing its point towards the soft tissues at various depths; any indication of pain caused by this act is pretty sure proof of nailing. It stands to reason that the character of the nail-holes in the shoe should be closely examined.

Treatment. — When the foot has sustained an ordinary simple prick with a nail, the latter should be left out and the hole well filled with wax. As a rule, no serious results follow. In severe direct nailing the entire shoeing should be most carefully examined, and only after everything is found to be right, and the shoe fits in such a manner that the nails can only penetrate the wall from the white line, can it be regarded as correct. The offending nail-hole is then to be closed with wax. According to the intensity of the wound we may expect a more or less pronounced inflammation of the pododerm, and this is to be combated by resting the animal and cooling the foot.

If the wound is clean and recent, enlarging the opening in the horn by cutting and boring can have no reasonable object; the wound by such an act will not be made smaller, but larger.

Frequently, however, the wound is not observed or suspected until the pain has become very intense (indirect nailing, nailpressure); in such cases the offending nail when withdrawn is apt to he covered with pus or a dark, thin, ill-smelling liquid. In such a case the liquid, whatever its nature may be, must be given free escape. In order to accomplish this it is entirely sufficient to cut away a section of the wall from the nailhole outward, not greater than the width of the little finger, and then to assist in the discharge of the pus by placing the foot in a warm bath; it is entirely wrong, in fact, reprehensible, to remove all horn of the wall and sole which has been loosened from the soft parts by the suppurative process. After the escape of the inflammatory fluids, the wall and sole will form the best-fitting and most suitable protective dressing for the diseased region until it has secreted new horn. If, after removal of the nail and pus, the pain does not diminish, warm disinfecting baths of one to two parts of creolin, or the same amount of lysol, to one hundred parts of water at a temperature of about 90° F. will be of especial benefit; they will not only soften the horn, but by their moisture and warmth will directly diminish the pain and have a healing influence upon the suppurating surfaces. The warm baths must actually be warm and be kept warm. Antiseptic solutions at room temperature are much less efficient.

If the pain has not been very pronounced, or if it has been greatly alleviated by two or three warm baths, then, as a rule, it is sufficient to put a few drops of creolin upon the inflamed surface, and to close the opening with oakum (carbolized oakum or carbolized cotton is better).

The horse which has been nailed will be again perfectly serviceable after a few days if shod with a shoe which does not press upon the inflamed region. The shoe does not press when it rests only upon the bearing-edge of the wall, when the white line and the edge of the sole are entirely free of the shoe, and no nails are driven in the immediate vicinity of the wound.

Even though, as we have seen, nailing in the great majority of cases is not particularly serious to the horse and owner, yet we should never forget that tetanus (lockjaw), a disease which is nearly always fatal to horses, may follow. Nailing, however insignificant it may seem, may under conditions lead to the death of the horse.

2. Street-Nail.

The condition caused by accidental injury of the sensitive structures covered by the horny sole, such as the velvety tissue of the sole and frog, plantar cushion, perforans tendon, navicular bone, os pedis, or the pedal articulation, by sharp objects, especially nails, is called “penetrating streetnail,” or simply “street-nail.” The resistance of the ground to the weight of the body drives these penetrating objects through the sole or frog in to the foot.

Hind hoofs are more often affected than fore-hoofs. A favorite point of entrance is the lateral lacuna of the frog. Street-nail is favored by excessive thinning of the sole and frog.

Symptoms. — The symptoms are, as a rule, sudden pain followed by lameness. The first assistance is usually sought in the shoeing-shop. If the cause of lameness be found to be a penetrating nail, piece of glass, or other pointed foreign body, it must be carefully drawn out, in doing which we should remove the entire object, not allowing pieces to break off and remain in the wound. Since it is always important to know in what direction and how deep the foreign body has penetrated, in order to be able to estimate the gravity of the wound, it is advisable in all cases to preserve the penetrating body, that it may be shown to the veterinarian, in case his services are required.

In slight injuries to the velvety tissue of the sole or frog, accompanied with moderate pain, it is of no benefit to enlarge the opening, though the horn of the sole or frog should be thinned for the space of an inch or more around the wound, followed by cooling applications. Deep, penetrating wounds accompanied with intense pain require the attention of a veterinarian.

Often some form of dressing is necessary, and this is usually held in place by a special shoe. For slight injuries, such splint-dressings as are shown in Figs. 188 and 189 are sufficient. Whether such a dressing be applied to the front or hind feet the shoe should be well concaved upon the hoof-surface. The dressing is held in place by thin splints of tough wood, which are firmly wedged between the shoe and hoof.

In those rare cases in which it is necessary to maintain continuous pressure upon the seat of the wound, and to protect the entire plantar surface of the hoof, a covered shoe (Figs. 190 and 191) is recommended. This shoe is provided with a sheet-iron cover, having at the toe a spur which fits into a corresponding hole in the toe of the shoe, and fastened at the heels by means of screw heel-calks.

3. Calk Wounds of the Coronet.

All tread-wounds of the coronet, caused by the calks of the opposite shoe, by the shoes of other horses, or by forging, are known as calk wounds, or simply as “calking.” The injury itself is either a bruise or a bruised wound, followed by inflammation of the coronary cushion and an interruption in the formation of horn at that point. It occurs most often in winter from sharp calks, especially on the hind feet. The common seat of the injury is the coronet of the toe and inner side of the foot.

The inflammation terminates either in resolution — that is, passes gradually away, leaving the tissues apparently normal — or in suppuration. The perioplic horn-band, which is usually loosened from the perioplic band by the injury, does not again unite. For this reason, and because of the interruption in the formation of horn at the seat of injury, there results a transverse depression or cleft in the wall.

The shoeing has to deal only with the lameness that may be present as a result of the calking. The section of the wall containing the lesion should be shortened, so that it will not press upon the shoe. Serious calk wounds, as a rule, require treatment by a veterinarian.