156 THJ^ CAT. [CHAP. V. 



The yluteus minimus arises from the ventral part of the outer 

 surface of the ilium behind and beneath the muscle last described ; 

 also from the anterior part of the ischium, above the acetabulum. It 

 is inserted also into the great trochanter. 



The fjhdeus quai'tits is a very small and delicate muscle which 

 arises in front of the acetabulum just outside the origin of the rectus 

 femoris. It is inserted into the front of the femur on the inner side 

 of the great trochanter, i.e., to the middle of the anterior inter- 

 trochanteric line, passing down between the vasti. 



The pyriformis takes origin from the ventral surface of the 

 sacrum. It passes out of the great sacro-sciatic notch (superficially 

 to the great sciatic nerve, and in close apposition to and somewhat 

 connected with the hinder surface of the gluteus minimus), and is 

 inserted into the great trochanter within the insertion of the gluteus 

 medius. This and the following muscles, up to and including the 

 quadratus femoris, rotate the hind limb outwards. 



The obturator externus arises from the outer surface of the ob- 

 turator membrane and the bony margin surrounding it. Passing at 

 first upwards and backwards, it ends in a strong tendon which turns 

 outwards, and is inserted into the trochanteric fossa. 



The obturator ijiternus arises from the inner surface of the ob- 

 turator membrane and its bony frame. Its fibres converge to a 

 tendon which ascends, curves round the ischium and passes out- 

 wards and forwards to be inserted into the trochanteric fossa. 



The gemellus anterior is a very smnll muscle which arises from the 

 spine of the ischium and is inserted into the anterior margin of the 

 tendon of the obturator internus. 



The gemellus posterior is a muscle similar to the last in size and 

 insertion, but which takes origin from the tuberosity of the ischium. 



The quadratus femoris is a muscle which proceeds from the 

 tuberosity of the ischium and the margin of the ischium below it, to 

 the posterior intertrochanteric line and posterior surface of the 

 femur at the lower end of the great trochanter (Fig. 83, A, Qf)- 



Psoas magnns is a large muscle arising from the interior of the 

 trunk and passing out beneath the brim of the pelvis. It arises 

 beside the diaphragm from the transverse processes of all the 

 lumbar vertebra), and is inserted into the lesser trochanter of the 

 femur (Ps). 



Iliacus. — This muscle is represented by fibres which arise from 

 the inner surface of the ilium and blend with the psoas magnus. 



The psoas parvus is but a subdi\nsion of the psoas magnus, which 

 subdivision ends in a strong tendon inserted into the ilio-pectineal 

 eminence. 



The quadratus luniborum is a muscle which arises (by a strong 

 tendinous origin) from the outer margin of the ilium, half an inch 

 behind its anterior end. Its fibres become closely connected with 

 those of the psoas magnus, along the under surface of the lumbar 

 transverse processes and onwards to the body of the twelfth dorsal 

 vertebra. 



