DEFECTS OF THE HORN CAPSULE
AND LATERAL CARTILAGES.
(a) Changes of form: 1, flat hoof and full hoof (dropped sole); 2, upright hoof (stumpy or stubby hoof); 3, contracted hoof; 4, wry hoof; 5, crooked hoof; 6, ossification of the lateral cartilage (side-bone).
(b) Disturbances of continuity of the horn capsule: 1, cracks; 2, clefts; 3, loose wall; 4, hollow wall; 5, thrush.
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 Usually the blood flows from the nail-hole, or the nail when withdrawn may merely show a bloodstain at its point; however, internal bleeding may occur without any external manifestations.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.