Action.—Adducts and rotates the femur and extends the tibia.
M. gracilis ([Fig. 91], b).—The gracilis is a flat, thin, subcutaneous muscle occupying the ventral half of the medial surface 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], i) and the adductor femoris ([Fig. 91], h).
Action.—Adducts the leg and draws it caudad.
M. adductor femoris (magnus et brevis) ([Fig. 92], g; [Fig. 90], h).—The adductor femoris lies between the semimembranosus ([Fig. 92], h) and the femur. Its proximal part is covered by the semimembranosus, while its distal part lies outside of it.
Origin by muscle-fibres from the rami of the pubis and the ischium along the whole of the length of the symphysis; from the ramus of the ischium between the symphysis and the tuberosity, and from the tendon of origin common to the two gracilis muscles.
Insertion into nearly the whole of the ventral surface of the shaft of the femur. The area begins at the base of the great trochanter opposite the proximal end and the insertion area of the gluteus maximus. It extends thence distad along the caudal border of the surface as an area about one millimeter wide. At the junction of the first and second thirds of the shaft the area expands and occupies the whole of the ventral surface of the bone, ending at the intercondyloid fossa.
Relations.—Lateral surface with the biceps ([Fig. 68], t), the great sciatic nerve ([Fig. 163], a), the tenuissimus ([Fig. 90], g), and the semimembranosus ([Fig. 92], h); dorsolateral border in contact with the vastus lateralis ([Fig. 92], c). Dorsal surface with the quadratus femoris ([Fig. 90], f) and obturator externus ([Fig. 90], e). Caudal surface with the semimembranosus ([Fig. 92], h). Medial surface with the gracilis ([Fig. 91], b), adductor longus ([Fig. 92], f), pectineus ([Fig. 92], e), vastus medialis ([Fig. 92], c), and distad with the medial head of the gastrocnemius ([Fig. 92], j).