LKiAMENTS AND MUSCLES OF THE HORSE. 55 



Gastrocnemius. 

 Origin.— By two heads, one from each side of the supracondy- 



loid fossa of the femur. 

 Lisertion.— To the middle of the summit of the os calcis. 

 Action. — To extend the hock. 

 3r^^g._A small synovial bursa is interposed between the tendon 



and the forepart of the summit of the os calcis. 

 Flexor pedis perforatus. 

 Q^,;gln.—'Froin ,the supracondyloid fossa. 

 Insertion.— To the summit of the os calcis, and to the sides of 



the OS coronae. 

 ji ctio7i.— To flex the pastern and fetlock, and to extend the 



hock. 

 ^Yo^^.— -This muscle is almost entirely tendinous in character. 

 Its tendon winds round the inner side of the gastrocnemius 

 tendon to reach the back of it, and the summit of the os 

 calcis. It plays over and forms a cap over the latter, to 

 which some fibres are attached, a synovial bursa being 

 interposed. An important action of this muscle is its 

 mechanical one of assisting the animal to stand, while the 

 hip and stifle joints are kept extended. 



SOLEUS. 



Origin.- -From the head of the flbula. 

 Insertio7i.—lt joins the tendon of the gastrocnemius 

 jl^tion.— To assist (very slightly), the gastrocnemius. 



POPLITEUS. 



Origin.— Yrom the lower depression on the external condyle of 



the femur. 

 Insertion.— To a triangular surface on the back of the tibia 



(above the oblique line) 

 Action.— To flex the stifle, and (slightly) to rotate it inwards. 



Flexor pedis perfor-A-ns. 



Origin.— From the posterior surface of the tibia below the ob- 

 lique line, from the external tuberosity, and from the flbula. 



