ANATOMY. 



border of the great trochanter. Action, to rotate the thigh inwards, also 

 to abduct and draw it forwards, and to maintain the trunk erect. Nerve, 

 superior gluteal. 



Pyriformis, 9 by 3 digitations from the front of the sacrum, from the margin 

 of the great sacro-sciatic foramen and the great sacro-sciatic ligament, into 

 the upper border of the great trochanter, 7 having passed through the great 

 sacro-sciatic foramen. Action, an external rotator of the thigh. Nerves, 

 branches from the sacral plexus. 



Obturator Interims, 11 front the posterior bony margin of the obturator 

 foramen and the inner surface of the obturator membrane, into the great tro- 

 chanter, 7 passing through the lesser sacro-sciatic notch. Action, an external 

 rotator of the thigh. Nerves, branches from the sacral plexus. 

 Gemellus Superior, 10 from the outer surface of the spine of the ischium, 

 into the great trochanter, being blended with the tendon of the obturator 

 internus. Action, an external rotator of the thigh. Nerves, branches from 

 the sacral plexus. 



Gemellus Inferior, 12 from the tuberosity of the ischium, into the tendon 

 of the obturator internus and the great trochanter. Action, an external 

 rotator of the thigh. Nerves, branches from the sacral plexus. 



FIG. 49. Obturator Externus, from the anterior 



inner bony margin of the obturator fora- 

 men, and the inner two-thirds of the 

 anterior surface of the obturator mem- 

 brane, into the digital fossa of the 

 femur at the inner base of the great 

 trochanter. Action, an external rotator 

 of the thigh. Nerve, obturator. 



Quadratus Femoris, 13 from the tuberosity 

 of the ischium, into the upper part of 

 the linea quadrati on the trochanter 

 major posteriorly. Action, an external 

 rotator of the thigh. Nerves, branches 

 from the sacral plexus. 

 Biceps, 16 by 2 heads, the Long Headd from 

 the tuberosity of the ischium posteri- 

 orly, the Short Head,* from the outer 

 lip of the linea aspera, and the inter- 

 muscular septum, into the outer side 

 of the head of the fibula ; its tendon embracing the external lateral ligament 

 of the kne joint, and forming the Outer Hamstring, the tendons of the semi- 



