158 MUSCULAR SYSTEM. 



extensor tendon expands itself, and continues to do so to its ter- 

 mination. 



Action. — In consequence of this tendon being bound down 

 upon the hock by the sheath through which it passes, it will have 

 effect in flexing that joint, at the same time that it is performing 

 its own special function, the extension of the foot, as well as the 

 pastern and fetlock joints. 



**# Immediately beneatli the bend of the hock, from the antero-superior 

 part of the metatarsal bone, issues a thin layer of fleshy fibres, enveloped in 

 cellular substance, and concealed in part by the tendon of the above muscle, 

 with which (about one-fourth of the length of the cannon downward) they 

 form a union, and make some addition to its substance. In action, these 

 supplementary fibres will brace the tendon ; and are probably furnished to 

 prevent it from being compressed by the flexion of the hock. 

 PERONEUS. — Pero?teo-prephalcuigeus. 



Situation. — Antero-external side of the limb. 



Form. — Cordiform; elongated; flattened from before back- 

 wards. 



Attachment. — Superiorly, to the head of the fibula, continu- 

 ing its attachment for the entire length of that bone. Inferiorly, 

 the same as the foregoing muscle. 



Relations. — Externally, with the faschia and skin ; internally, 

 with the fibula ; anteriorly, with the extensor pedis ; posteriorly, 

 with the flexor pedis. 



Structure. — Superior attachment, fleshy and tendinous, from 

 which a fleshy belly descends nearly the whole length of the 

 tibia: a slender tendon, in form a flattened cord, then com- 

 mences, which passes through a distinct tendinous sheath, across 

 the front of the hock, and upon the cannon bone forms a con- 

 nexion with the tendon of the flexor pedis. 



Action.— It will co-operate with the extensor pedis. 

 FLEXOR METATA Hsi. — Tihio-prematarseus. 



Situation. — Antero-internal side of the limb. 



Figure. — Bifurcate at either extremity. 



Attachment. — Superiorly, in common with the extensor pedis, 

 from the external condyle of the os femoris ; and from a broad 

 triangular excavation marked upon the superior and antero- 

 external part of the tibia. Inferiorly, to the head of the large 

 metatarsal bone, and to that of the internal small metatarsal 

 bone. 



Structure. — The tendon by which the flexor pedis is attached, 

 superiorly, enters afterwards into the composition of the present 

 muscle, whose fleshy belly, although in intimate connexion with 

 the tendon, is ])laced behind it. In front of the hock, the fleshy 

 part ends in a small cordiform tendon, which is enveloped by a 



