ANATOMY OF THE HORSE. 123 
the sartorius: posteriorly, with the femoral bone ; anteriorly, with 
the faschia lata. 
Structure. —Covered bv a thin aponeurosis; otherwise, fleshy. 
The aponeuroses proceeding* irom the vasti extend downward 
over the patella to be fixed to the tubercle of the tibia. Infe- 
riorly, an aponeurotic tendon separates it from the crureus. 
t CRUREUS VEL CRURALIS. 
(Middle Head of the Tri-femoro-rotuleus.) 
$ 
Situation. —Deep-seated in the hollow formed by the rectus 
above, the vasti on either side, and the femoral bone below. 
Form. —Fusiform; elongated* 
Attachment. —Antero-superiorly, to the ileum, just above the 
acetabulum ; postero-inferiorly, to the body of the femoral bone 
and to the patella. 
Relations. —With the muscles and bone to which it lies con- 
tiguous. 
Structure. —Tendinous at its extremities; intermediate parts, 
fleshy ; under part, aponeurotic. 
Action of the two Vasti and the Crureus , considered as a 
Triceps or one entire Muscle. 
In consequence of their connexion, through the intervention of 
the patella and its ligaments, with the tibia, these muscles be¬ 
come direct extensors of the thigh; and their power as such is 
considerably enhanced by the peculiar construction of the stifle- 
joint, which enables them to act with the combined mechanical 
advantages of pulley and lever. In progression, they raise the 
thigh forwards and advance it under the body; and, in that po¬ 
sition, as soon as the limb has become a fixed point, they will 
assist in progressing the haunch. 
INTERNAL ILIO FEMORAL REGION, 
Comprehends the muscles forming the prominent rotundity of 
thi nner part of the haunch. 
sartorius.— Sub-lumbo-tibialis. 
m 
Situation .— Antero-internal part of the haunch. 
Form. —Long, slender, pyramidal; anterior part broadest. 
Attachment. —Antero-superiorly, to the bodies of the posterior 
lumbar vertebrae, and to the brim of the pelvis midway between 
the symphysis pubis and the anterior spinous process of the ileum ; 
inferiorly, to the supero-internal part of the tibia, and to the in¬ 
ternal condyle of the femoral bone. 
