398 MUSCLES. 



It is? covered behind by the tendinous origin of the transver- 

 salis abdominis, which separates it from the sacro-Iumbalis and 

 from the longissimus dorsi. It may also be seen very well 

 from behind, in the dissection of the back.* 



The Psoas Parvus, 



Arises, fleshy, from the contiguous edge of the body of the 

 Jast dorsal and of the first lumbar vertebra at their sides, and 

 from the intervertebral ligament. It is at the anterior and in- 

 ternal edge of the psoas magnus; has a short belly, and a long 

 tendon by which it is inserted into the linea innominata, about 

 half-way between the spine of the pubes and the junction of 

 this bone with the ilium. The tendon, besides, is expanded into 

 the fascia iliaca. 



Its use seems to be, to draw upwards the sheath of the fe- 

 moral vessels, which is derived from the fascia iliaca, and, con- 

 sequently, to draw upwards the vessels themselves; which pro- 

 bably diminishes the liability to injury from their too great or 

 sudden flexion. This muscle is sometimes wanting. 



The Psoas Magnus. 



Arises, fleshy, from the side of the body of the last dorsal 

 and of the four upper lumbar vertebrae, and from the transverse 

 processes of all the lumbar vertebrae. It forms an oblong fleshy 

 cushion on the side of the lumbar vertebrae, and constituting the 

 lateral boundary of the inlet to the pelvis, it passes out of the 

 pelvis, under Poupart's ligament, about its middle. 



It is inserted tendinous, into the trochanter minor of the os 

 femoris, and fleshy for an inch below it. 



It bends the body forwards, or draws the thigh upwards.f 



* Varieties. Sometimes a broad tendon from it is inserted into the inferior 

 margin of the body of the eleventh vertebra of the back. Sometimes a fascicu- 

 lus of it touches the margin of the eleventh rib, near its head, and above the in- 

 tercostal vessels. 



j- Varieties. Sometimes it is joined by muscular fasciculi from the first, se- 

 cond, and even the third bone of the sacrum. Sometimes, where it borders on 

 the pelvis, there is a small fasciculus, which continues distinct almost to the tro- 

 chanter minor, and then sends its own tendon into the common tendon of the 

 iliacus interims and psoas magnus. 



