198 THE MUSCLES. 
Jusertion on a long S-shaped line which begins on the 
dorsal border of the tibial shaft about two centimeters from its 
proximal end, passes thence to the middle of the proximal end 
of the medial surface of the tibia, thence across the ligaments 
of the knee-joint and the medial surface of the medial epicondyle 
to the patella, crosses the patella obliquely to the middle of its 
proximal end, and may be continued for some distance proximad 
along the middle line on the fascia. 
Relations.—Medial surface with the integument and proxi- 
mad with the internal oblique muscle (Fig. 68, f). Lateral 
(inner) surface with the tensor fascie late (Fig. 68, 7), the 
vastus lateralis (Fig. 90, @), the superficial fascia, the vastus 
medialis (Fig. 92, c), the rectus femoris (Fig. 92, 4), and the 
distal end of the semimembranosus (Fig. 92, 4’). 
Action.—Adducts and rotates the femur and extends the 
tibia. ; 
M. gracilis (Fig. 91, 4).—The gracilis is a flat, thin, sub- 
cutaneous muscle occupying the ventral half of the medial sur- 
face of the thigh. 
Origin by a strong tendon from the caudal three-fourths of 
the symphysis of the ischium and pubis. The tendon may 
extend caudad of the symphysis in the middle line to the level 
of the tuberosity of the ischium. For about its first centimeter 
the tendon is common to the two muscles of opposite sides and 
gives origin on two sides to the fibres of the adductor femoris. 
The common tendon divides into two which pass laterad, each 
ending in a convex border from which the muscle-fibres 
spring. 
Insertion.—It ends in a thin aponeurosis, part of which is 
continuous with that of the sartorius. The aponeurosis is finally 
inserted into the medial surface of the tibia near its proximal 
end, while distally it is continuous with the fascia. 
Relations.—Outer (medial) surface with the integument. 
Inner (lateral) surface with the semimembranosus (Fig. 91, 7) 
and the adductor femoris (Fig. 91, /). 
Action.—Adducts the leg and draws it caudad. 
M. adductor femoris (magnus et brevis) (Fig. 92, ¢; Fig. 
90, 4). —The adductor femoris lies between the semimembrano- 
