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THE MUSCULAK SYSTEM. 



Piriformis 

 (insertion) 

 Glutseus medius 

 (insertion) 



obturator intemus and 



skeleton; and another element, the iliacus, extending between the hip bone 

 and the femur. The. muscles chiefly occupy the posterior wall of the abdomen 

 and pelvis major, only their lower parts appear in the thigh below the inguinal 

 ligament, in the lateral part of the femoral triangle. 



M. Psoas Major. The psoas major is a large piriform muscle, which has an 

 extensive origin, by fleshy fibres, from the vertebral column in the lumbar region. 

 It arises from (1) the intervertebral fibro-cartilages above each lumbar vertebra, 

 and the adjacent margins of the vertebrae from the inferior border of the 12th 

 thoracic to the superior border of the 5th lumbar vertebra ; (2) it arises also 

 from four aponeurotic arches which pass over the sides of the bodies of the 

 first four lumbar vertebrae ; and (3) it has an additional origin posteriorly from the 



transverse processes of all the 

 lumbar vertebrae. The fibres form 

 a fusiform muscle which projects 

 over the superior aperture of the 

 pelvis and passes behind the 

 inguinal ligament, to end in a 

 tendon which is inserted into the 

 apex of the lesser trochanter of 

 the femur (-Fig. 365). A bursa, 

 which may be continuous with 

 the synovial cavity of the hip- 

 joint, separates the tendon from 

 the pubis and the capsule of the 

 hip-joint. 



M. Psoas Minor. The psoas 

 minor (O.T. parvus) is often 

 absent (40 per cent). It arises 

 from the intervertebral fibro-car- 

 tilage between the last thoracic 

 and first lumbar vertebras, and 

 vastus medians (origin) from the contiguous margins of 

 those vertebras. The muscle is 

 closely apposed to the anterior 

 surface of the psoas major. 



It forms a slender fleshy belly, 

 and is inserted, by a narrow tendon, 

 into the middle of the linea 

 terminalis and the ilio-pectineal 

 eminence, its margins blending 

 with the fascia covering the psoas 

 major. 



M. . Iliacus. -- The iliacus 

 muscle arises in the pelvis major 



by fleshy fibres, mainly from a horseshoe-shaped origin around the margin of the 

 iliac fossa ; it has additional origins also from the ala of the sacrum, the anterior 

 sacro-iliac, lumbo-sacral, and ilio-lumbar ligaments, and outside the pelvis, from 

 the proximal part of the capsule of the hip-joint (ilio-femoral ligament). It is 

 a fan-shaped muscle, and its fibres pass distally over the hip-joint towards the lesser 

 trochanter of the femur. 



Lying lateral to the psoas muscle, it passes through the femoral triangle, 

 and is inserted by fleshy fibres (1) into the lateral side of the tendon of the psoas 

 major ; (2) into the concave anterior and upper surfaces of the lesser trochanter ; 

 and (3) into the body of the femur distal to the lesser trochanter for about an inch 

 (Fig. 365); and (4) by its most lateral fibres into the capsule of the hip-joint. 

 These fibres are often separate, forming the iliacus minor, or iliocapsularis. 



Nerve-Supply. The psoas major is supplied directly by branches from the anterior rami of 

 the second and third lumbar nerves with additional branches in some cases from the first and fourth. 



Glutseus maximus 

 (insertion) 



Adductor niagnus 

 (insertion) 



Adductor brevis 

 (insertion) 



FIG. 365: MUSCLE- ATTACHMENTS TO THE POSTERIOR ASPECT 



OF THE PROXIMAL PART OF THE LEFT FEMUR, 



