THE LOWER LIMB 465 



Origin. — (i) The outer lip of the crest of the ilium for i^ inches 

 at its anterior part ; (2) the dorsum ilii for \ inch close to the 

 upper part of the anterior interspinous notch ; and (3) the fascia 

 lata covering the muscle. 



Insertion. — ^The angle of division of the ilio;- tibial band of the 

 fascia lata into a superficial and deep lamina, at the junction of the 

 upper fourth and lower three-fourths of the thigh. 



Nerve-supply. — ^The lower di\Tsion of the superior gluteal nerve 

 from the sacral plexus, the branch of which enters the muscle on 

 its deep surface. 



Action. — (i) Abductor and internal rotator of the thigh ; and 

 (2) extensor of the knee-joint. The muscle, in association with, 

 the gluteus maximus, takes part in the completion of extension of 

 the knee-joint, and in the maintenance of extension through means 

 of the ilio-tibial band, as in standing. 



The tensor fasciae femoris is a flat, strap-like muscle, the direc- 

 tion of which is downwards, with a slight inclination outwards 

 and backwards. 



Ilio-Psoas. — The femoral portion of this muscle is alone described 

 in this place. For a full description of the psoas magnus and 

 iliacus, see Abdomen Section. The ilio-psoas is inserted into the 

 small trochanter of the femur, the outer fibres of the iliacus taking 

 insertion into the triangular surface which is situated below and in 

 front of the small trochanter, between it and the spiral line. 



The outer portion of the muscle, which is fleshy, represents the 

 ihacus, and the inner portion, which is tendinous, represents the 

 psoas magnus. Lying deeply between the two is the anterior 

 crural nerve ; tlie femoral arten»', enclosed within the femoral sheath, 

 rests upon the psoas magnus; and the femoral vein, similarly 

 enclosed, lies between the psoas magnus and pectineus. The ilio- 

 psoas covers the front of the capsular ligament of the hip- joint, 

 a bursa inter\'ening between the psoas portion and the ligament. 



Pectineus — Origin. — (i) The pectineal portion of the ilio-pectineal 

 line of the os pubis ; (2) the adjacent portion of the upper or pec- 

 tineal surface of the superior pubic ramus ; and (3) the pubic 

 lamina of the fascia lata, as it covers the muscle in this situation. 



Insertion. — The upper third of the line which leads from the back 

 of the small trochanter of the femur to the inner lip of the linea 

 aspera. 



Nerve-supply. — ^The anterior division of the anterior femoral nerve, 

 the branch from which passes inwards behind the femoral sheath, and 

 enters the superficial surface of the muscle close to its outer border. 

 The pectineus sometimes receives an additional nerve from the 

 anterior division of the obturator, or from the accessory obturator 

 (when present), which enters the deep surface of the muscle. 



Action. — (i) Flexion of the hip-joint, and (2) adduction and 



xternal rotation of the thigh, as, for example, in crossing one leg 

 over the other. 



The pectineus is a flat, four-sided muscle, which is directed doMm- 



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