[Fig. 90].—Muscles on the Lateral Side of the Leg, after Removal of the Muscles shown in [Fig. 68] (Biceps, Tensor fasciæ latæ, Caudofemoralis, and Gluteus maximus).

a, M. sartorius; b, M. gluteus medius; c, M. rectus femoris; d, M. vastus lateralis; e, M. obturator internus; f, M. quadratus femoris; g, M. tenuissimus; h, M. adductor femoris; i, M. semimembranosus; j, M. semitendinosus; k, M. vastus intermedius; l, M. plantaris; m, m′, m″, M. gastrocnemius, outer head (m, part from the external sesamoid bone; m′, from the plantaris; m″, from the superficial fascia); n, M. tibialis anterior; o, M. soleus; p, M. extensor longus digitorum; q, M. peroneus longus; r, M. peroneus tertius (r′, its tendon); s, M. peroneus brevis; t, tendon of Achilles; u, M. extensor brevis digitorum. 1, great trochanter of femur; 2, tuberosity of ischium, with cut origin of M. biceps femoris; 3, patella; 4, calcaneus; 5, transverse ligaments; 6, lateral malleolus.

Insertion into the proximal portion of the bottom of the trochanteric fossa.

Relations.—Ventral surface with the adductor femoris ([Fig. 92], g). Dorsal surface with the pubis and ischium. Caudal border with the quadratus femoris ([Fig. 90], f).

Action.—Assists the iliopsoas.

B. Muscles on the Medial Surface of the Hip.

—M. obturator internus ([Fig. 90], e).—The obturator internus appears as a triangular muscle caudad of the gemellus superior.

Origin by numerous small separate heads from the dorsal surface of the ramus of the ischium along its symphysis and following its medial border from the symphysis nearly to the tuberosity. The fibres form a flat muscle which narrows and passes through the lesser sciatic notch, turns ventrad and ends in a strong flat tendon whose

Insertion is into the bottom of the trochanteric fossa of the femur. The tendon is continued proximad on the inner surface of the muscle and forms a smooth firm surface by which the muscle glides over the dorsal border of the ischium. Into the inner surface of this tendon near its insertion the tendon of the gemellus inferior is inserted.