=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_). _Action._--An extensor of the thigh. =M. adductor longus= (Fig. 91, _g_; Fig. 92, _f_).--A thin muscle which covers the dorsal half of the medial surface of the adductor femoris (Fig. 92, _g_). _Origin_ by muscle-fibres from the median three-fourths of the cranial border of the pubis, the line of origin forming a medial continuation of that of the pectineus (Fig. 92, _e_). _Insertion_ by a thin aponeurosis into the external linea aspera of the femur along the second and third fifths of the bone. _Relations._--With its medial or cranial surface the adductor longus forms part of the boundary of a depression among the muscles at the proximal end of the medial side of the leg. This depression is called the iliopectineal fossa; it contains the femoral vein and artery and saphenous nerve imbedded in fat (Fig. 127). The medial edge of the adductor longus is in relation with the integument; the lateral edge with the pectineus (Fig. 92, _e_). Inner or caudal surface with the adductor femoris (Fig. 92, _g_). _Action._--Adductor of the thigh. [Illustration: FIG. 92.--SECOND LAYER OF MUSCLES ON THE MEDIAL SIDE OF THE THIGH.