830 FLEXOB TENDONS AND SUSPENSORY LIGAMENT. 



succeeded by tendon. In close contact throughout with the perforans, 

 the tendo-perforatua passes through the carpal arch to near the fetlock, 

 where it forms a sheath-like ring for (he peiforans, then descending and 

 becoming somewhat broader it terminates by a bifid insertion on the os 

 ooronse. Before entering the carpal arch the 1 perf oratus is joined by the 

 radial ligament, which hitherto has attracted little attention outside flie 

 dissecting room. 



The radial ligament arises from the inner border of the posterior 

 surface of the lower extremity of the radius and extends obliquely down- 

 ward and outward to join the peiforatus tendon. It is a short, rather lax 

 fibrous band, between two and three inches long, about an inch broad, 

 and less than half an inch thick. Recently in Germany and France, cases 

 of lameness have been attributed to strain of this ligament. 



The suspensory ligament, arising from the lower row of carpal bones 

 and the head of the cannon, descends between the sub-carpal ligament 

 and metacarpus to near the " buttons" where it bifurcates. Each branch 

 is implanted on the excentric surface of the corresponding sesamoid, and 

 a portion of each band is continued downward and forward to join the 

 extensor pedis tendon. Prom its origin to the point of bifurcation the 

 suspensory is flattened and closely applied to the cannon, its branches to the 

 sesamoids are rounded, and the extensor bands are flat. It has a covering 

 of connective tissue which attaches it to the cannon and flexor 

 aponeurosis, in structure it differs from the tendons by containing 

 fasciculi of striped muscle and some fat. 



Hind limb. Apart from their points of origin and a few other differences, 

 the more important features of the posterior flexors are: — the perforans 

 in the tarsal arch is not accompanied by the peiforatus ; at the upper 

 metatarsal region it is joined by the tendon of the accessory flexor muscle, 

 and near the middle of the shank by the subtarsal ligament, which though 

 longer is less thick or strong than the sub-carpal ligament. The perforatus 

 has a very short muscular portion, and its tendon, beginning just below 

 the upper third of the tibia, after a winding course, reaches the point of 

 the hock, where it forms a cap which is attached laterally to the summit of 

 the os calcis. Below the hock the peiforatus descends the shank, as in 

 the fore limb, to the os corona*. 



Peritendineum. Each tendon has its own covering of connective 

 tissue. This is composed of several laminae, more or less united, closely 

 investing the tendon, continuous inwardly with the interfascicular septa, 

 and connected outwardly, according to the part examined, with the visceral 

 layer of the flexor synovial sheath, the common aponeurosis, or the 

 adjoining tendon or ligament. Between its laminae the vessels and nerves 

 break up to penetrate the interfascicular septa of the tendon. 



Aponeurosis. The metacarpo-phalangean or common aponeurosis 

 furnishes a subcutaneous covering to the flexor tendons and subcarpal 

 ligament, and separates these from the suspensory. It consists of two 

 principal layers of fibrous tissue, united to each other and to the tendons 

 or parietal synovial sheath by areolar tissue and continuous with the 

 posterior wall of the carpal arch and fascia of the fore-arm. It forms a 

 strong fibrous brace for the flexor tendons at the sesamoids and pastern, 

 and supports and protects the vessels and nerves. In the hind limb the 

 metatarso-phalangean aponeurosis is similarly arranged. 



Synovial sheaths. Facilitate movement of the tendons, and consist 



