466 



A MANUAL OF ANATOMY 



wards, outwards, and backwards. The surfaces at first look 

 forwards and backwards, but, towards its insertion, the muscle 

 undergoes a slight twist, and its surfaces are then external and 

 internal. Its deep surface is related to the capsular ligament of 

 the hip- joint, the anterior division of the obturator nerve, and the 

 adductor brevis. 



Quadriceps Extensor Cruris. — This is a composite muscle, which 

 consists of the rectus femoris, vastus externus, crureus, and vastus 

 internus. The rectus femoris arises from the os innominatum, 



Twelfth Rib 



Quadratus Lumborum — 



Psoas Parvus 



Psoas Magnus 



Pyriformis - 



^Iliacus 



Small Sacro-sciatic 



Ligain£nt 



Great Sacro-sciatic 

 r - Ligament 



Obturator Externus 



Fig. 229. — The Psoas, Iliacus, and Quadratus I.umborum Musci.es. 



whilst the other three muscles take origin from the femur, the crureus 

 being situated between the vastus externus and vastus internus. 



I. Rectus Femoris — Origin. — By two strong tendinous heads- 

 anterior or straight, and posterior or reflected. The anterior or 

 straight head arises from the anterior inferior iliac spine. The 

 posterior or reflected head arises from the groove on the anterior 

 part of the dorsum ilii immediately above the brim of the aceta- 

 bulum, where it is under cover of the gluteus minimus. The two 

 heads unite at an angle of about 60 degrees. 



