ANATOMY OF THE HORSE. 
243 
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Attachment .—Superiorly, to the head of the fibula; inferiorly, 
(in union with the tendon of the gastrocnemius externus) to the 
os calcis. 
Relations. —Externally, with the skin; internally and poste¬ 
riorly, with the gastrocnemius externus; anteriorly, with the 
deep posterior crural muscles. The third popliteal nerve crosses 
its superior extremity. 
Structure. —This is the most slender muscle, in proportion to 
its length, in the body. Its delicate belly, composed of pale 
fleshy fibres, and constituting two-thirds of its length, sends off 
an equally delicate cordiform tendon, which unites inseparably, 
just above the hock, with the external tendon. 
3 —DEEP POSTERIOR FEMORO-CRURAL REGION. 
The muscles contained in this region lie deep-seated, in the 
interspace between the tibia and the gastrocnemii. They are 
covered and tensely bound down by a dense firm tendinous 
faschia. 
• ^ 
popliteus. — Femoro-tibialis Obliquus. 
Situation .—At the back of the stifle-joint. 
Form. —Short; thick; triangular. 
Attachment .—Superiorly, to the postero-external side of the 
outer condyle of the femur, and to the capsular ligament of the 
stifle-joint. Inferiorly, to the upper half of the inner side of the 
body of the tibia. 
Relations. —Posteriorly, with the gastrocnemii internus et 
externus, the semilunar cartilages, the postero-internal side of 
the head and the superior part of the body of the tibia: also, 
with the popliteal artery and vein. Externally, w T ith the internal 
lateral ligament; internally, with the gastrocnemius externus. 
Superiorly, w ith the condyles of the femur ; inferiorly, w ith the 
flexor pedis accessorius. 
Direction .—Of the superior fibres, nearly transverse ; of the 
inferior , obliquely inward and downward. 
Structure. —Its supero-external attachment consists of a 
flattened and partially cleft tendon, which plays over the back of 
the outer semilunar cartilage. This tendon is inclosed within a 
duplicature of the capsular ligament; but (notwithstanding that) 
is shutout by the internal fold of that duplicature from the cavity 
of the stifle joint. The tendon finally sinks into the fleshv part 
of the muscle, whose substance still in places discovers some 
scanty tendinous intersections. 
Action. —’To bend the stifle; and at the same time to turn the 
