MUSCLES OF THE PELVIC LIMBS 189 
Origin by fleshy fibres from the tips of the transverse 
processes of the last two sacral and the first caudal vertebre. 
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. 4) and the gluteus maximus. Inner surface with the 
gemellus superior (Fig. 163, 6), the great sciatic nerve (Fig. 
163, a), and the flexor caudz longus (Fig. 68, x). 
Action:—Abductor of the thigh. 
M. gemellus superior (Fig. 163, 6).—-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, 4), 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, ¢). 
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, 4) 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. 
