MUSCLES OF THH PELVIC LIMBS. 189 



Origin by fleshy fibres from the tips of the transverse 

 processes of the last two sacral and the first caudal vertebrae. 

 The muscle passes laterad through the great sciatic notch to its 



Insertion by a flat tendon into an elongated area on the 

 proximal border of the great trochanter just outside (caudad) 

 of the insertion of the gemellus superior. 



Relations. — Outer surface with the gluteus medius (Fig. 

 90, b) and the gluteus maximus. Inner surface with the 

 gemellus superior (Fig. 163, 6), the great sciatic nerve (Fig. 

 163, a), and the flexor caudae longus (Fig. 68, x). 



Action. — Abductor of the thigh. 



M. gemellus superior (Fig. 163, c). — The gemellus superior 

 is a triangular muscle lying beneath the pyriformis (Fig. 

 163, 7). It is broader than the pyriformis, so that it projects 

 beyond its borders both caudad and craniad. It is closely 

 united craniad with the gluteus minimus, so that the limits of 

 the two are definable only with difficulty. Its caudal border 

 is closely united to the gemellus inferior. 



Origin by fleshy fibres from an elongated area on the dorsal 

 border of the ilium and ischium. The area is narrowed craniad. 

 It does not quite reach the posterior inferior iliac spine in the 

 one direction nor the spine of the ischium in the other direction. 

 The fibres converge to a strong tendon the 



Insertion of which is into a triangular area dorsad of the tip 

 of the great trochanter. 



Relations. — Outer surface with the gluteus medius (Fig. 

 90, /;), the pyriformis (Fig. 163, 7), the great sciatic nerve 

 (Fig. 163, a), and the gluteus maximus. Inner surface with 

 the ilium, ischium, the capsularis, the caudal edge of the 

 gluteus minimus (Fig. 163, 5), and the cranial edge of the 

 obturator internus (Fig. 90, r). 



Action. — Rotates the femur and abducts it so as to carry 

 the foot outward. 



M. gluteus minimus (Fig. 163, 5). — The gluteus minimus 

 is a long triangular muscle beneath the middle of the gluteus 

 medius (Fig. 90, b) and with its caudal border against or 

 covering the cranial border of the gemellus superior (Fig. 

 163, 6), to which it is frequently closely united. 



X 



