THE MUSCLES OF THE HIND-LIMB, 67 
1. Muscles of the thigh. 
Remove the skin from one of the legs of the frog and clean the 
muscles first of the preaxial and then of the postaxial surfaces. 
a. Superficial muscles of preaxial (apparent ventral) 
surface. 
i, The sartorius: a long narrow muscular band which 
: crosses the thigh somewhat obliquely from the 
outer to the inner side. It arises from the iliac 
symphysis below the acetabulum, and is inserted 
into the inner side of the head of the tibia. 
ii. The adductor magnus: a large muscle lying along 
the inner border of the sartorius, but passing 
beneath it at its distal end. It arises from the 
pubic and ischial symphyses, and passes under 
the sartorius to be inserted into the distal third 
of the femur. 
iii. The adductor longus: a long narrow muscle lying 
along the outer side of the adductor magnus, 
and almost completely hidden by the sartorius: 
it arises from the iliac symphysis beneath the 
sartorius, and unites a little way beyond the 
middle of the thigh with the adductor magnus. 
. The rectus internus major: a large muscle lying 
along the inner side of the adductor magnus 
by and the sartorius. It arises from the ischial 
symphysis and is inserted into the head of the 
tibia. } 
v. The rectus internus minor: a narrow flat band of 
muscle running along the inner (flexor) margin of 
the thigh: it arises from a tendinous expansion 
connected with the ischial symphysis, and is 
inserted into the inner side of the tibia just 
below its head. 
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b. Superficial muscles of extensor surface of thigh. 
us vi. The triceps extensor femoris: the great extensor 
muscle of the thigh: it arises by three distinct 
origins, which may be described separately, and 
is inserted into the tibia just below its head. w . 
