DISSECTION OF THE ANTERIOR LIMB. 35 



behind the metacarpus. Having arrived at the fetlock, there is formed 

 in it a remarkable ring, through which the tendon of the deep flexor 

 plays. It is in consequence of this arrangement that the superficial 

 muscle is termed perforatus, and the deep one perforans. As already 

 seen, the tendons are here enveloped by the synovial membrane of the 

 metacarpophalangeal sheath. k.t its lower extremity the tendon is 

 bifid, and each slip is inserted into the upper extremity of the second 

 phalanx on its lateral aspect. 



Action. — The muscle flexes successively the pastern, fetlock, and 

 carpal joint. 



The Deep Flexor Tendon (Plates 5, 9, 10, and 11) is throughout 

 its course closely related to the preceding, in front of which it lies. 

 After descending through the carpal sheath, it is joined by a very 

 strong fibrous band — the subcarpal ligament, which is the downward 

 continuation of the posterior common ligament of the carpus. This 

 fuses *vith the tendon about the middle of the metacarpus, and it 

 is of considerable importance, being generally involved in what is 

 commonly termed "sprain of the back tendons." In that condition 

 it may be very distinctly felt by manipulating in front of the flexor 

 tendons, just below the carpus. The tendon, as thus reinforced, descends 

 between the suspensory ligament in front and the perforatus tendon 

 behind ; and at the fetlock it glides over the sesamoid pulley, and 

 passes through the ring of the superficial flexor. It then passes 

 between the terminal branches of the last-mentioned muscle, glides 

 over the smooth surface on the back of the second phalanx, plays over 

 the navicular bone, and finally becomes inserted into the semilunar 

 crest of the os pedis. The terminal portion of the muscle, as well 

 as the navicular sheath developed in connection with it, will be 

 examined with the parts contained within the hoof. 



Action. — The muscle flexes successively the interphalangeal joints, 

 the fetlock, and the carpus. 



THE FOOT. 



Directions. — By the term foot, as here applied, is meant the hoof and 

 the parts contained within it. If it is intended to study this in a limb 

 the whole of which is to be successively dissected, the student must 

 proceed in the following manner. When the dissection of the fore-arm 

 has been completed, and before the removal of the skin from the 

 metacarpus and digit, the hoof must be forcibly removed by the aid 

 of a shoeing-smith's hammer, toe-knife, and pincers. To facilitate this, 

 the hoof may be heated in a fire, the skin of the digit being swathed 

 in a wet cloth to prevent charring. This is the speediest method of 

 removing the hoof, but it has the double disadvantage of destroying 

 in great measure the hoof itself, and also the injection of the vessels, 



