528 A MANUAL OF ANATOMY. 



spinous processes and bone between them, from the capsule 

 of the hip joint. 



Insertion. Into the outer border of the tendon of the 

 psoas, also into an inch of the line from the lesser tro- 

 chanter to the linea aspera. 



Nerve Supply. By branches from the anterior crural, 

 derived from the second and third lumbar nerves. 



Actions. The psoas magnus and iliacus act as one mus- 

 cle upon the femur. They are the direct and most power- 

 ful flexors of the thigh, upon the abdomen, or the reverse. 

 From the insertion of their tendon into the lesser trochanter, 

 this insertion being outside of the centre of motion of the 

 head of the femur in the acetabulum. It follows that 

 flexion being arrested, the great trochanter will be raised 

 (carried forward) and internal rotation will result. 



Psoas Parvus. Fig. 107. 



When present this muscle will be found arising from the 

 intervertebral disc between the bodies of the last dorsal and 

 first lumbar vertebrae, and from the adjacent portions of 

 those vertebrae. 



Insertion. Into the iliopectineal line. 



Nerve Supply From the first lumbar nerve. 



Action. To flex the pelvis on the spine or the reverse. 



Quadratus Lumborum. Figs. 106, 107. 



Origin. From the iliolumbar ligament, from the inner 

 lip of the crest of the ilium for two inches posterior to the 

 iliolumbar ligament, from the tips of the transverse pro- 

 cesses of the three lower lumbar vertebrae. 



Insertion. Into the inner half of the lower border of the 

 last rib, and the transverse processes of the three upper 

 lumbar vertebrae. 



