_Origin_ by a flat tendon from the ventral surface of the os magnum on the ulnar side of the adductor pollicis (_b_). It passes toward the ulnar side and distad, the fibres diverging to their _Insertion_ (1) into nearly the whole of the radial surface of the fifth metacarpal, (2) into the base of its first phalanx. V. MUSCLES OF THE PELVIC LIMBS. =1. Muscles of the Hip.= A. ON THE LATERAL SURFACE OF THE HIP. =Fascia of the Thigh.=--After the removal of the superficial fascia with its fat and blood-vessels, there is seen a strong glistening fascia, the =fascia lata= (Fig. 68, _z_, page 117), covering the vastus lateralis muscle over the dorsal half of the thigh. Ventrally it dips between the vastus lateralis and the biceps femoris and, becoming gradually thinner, is lost on the surface of the former muscle. Passing over the dorsal border of the thigh, it extends beneath the sartorius and is attached to the dorsal border of the vastus medialis. Toward its distal end the fascia is continuous with the tendon of the biceps femoris and dorsad with the border of the sartorius muscle, while between these points it is united with the tendon of the vastus lateralis; it thus gains insertion into the patella. At its proximal end the fascia receives the insertion of the tensor fasciæ latæ (Fig. 68, _r_). =M. tensor fasciæ latæ= (Fig. 68, _r_, page 117; Fig. 92, _a_).--The tensor fasciæ latæ is a thick triangular muscle which may be recognized by its insertion into the proximal end of the fascia lata (Fig. 68, _z_; Fig. 92, _a′_). _Origin_ by fleshy fibres as a thick triangular prism from the outer margin of the ventral border of the ilium craniad of the auricular impression and from the fascia covering the ventral border of the gluteus medius (Fig. 90, _b_) over its cranial half. The caudal border of the muscle may be continuous with the cranial border of the gluteus maximus. The muscle spreads out in a fan-like manner, covering the proximal third of the dorsal surface of the thigh. The cranial fibres pass farther distad than the others. _Insertion_ into the fascia lata (Fig. 68, _z_) along an irregular line which begins caudad at the base of the great trochanter and ends on the cranial side of the thigh at the junction of the first and second thirds. _Relations._--Outer surface with the cutaneus maximus (Fig. 62, _b_, page 94) and craniad with the sartorius (Fig. 68, _q_). Cranial border with the sartorius (_q_); caudodorsal border with the gluteus medius (Fig. 90, _b_). Inner surface with the gluteus medius, the rectus femoris (Fig. 92, _b_), and the vastus lateralis (Fig. 90, _d_). _Action_ indicated by the name. It also assists the quadriceps femoris in extending the leg. =M. gluteus maximus.=--The gluteus maximus is a rather small quadrangular muscle in the angle between the gluteus medius (Fig. 90, _b_) and the caudal vertebræ.