THE .\BDOMEN AND ITS CONTENTS IIQ 



65. Psoas muscles: Ribs, centra, and transverse processes 

 of vertebrae from the eighth to the last sacral; to innominate 

 bone and femur. These muscles flex the back and are essen- 

 tially antagonistic to the sacrolumbalis group (59). They 

 form the mass of muscle lying on either side of the abdominal 

 aorta. 



6$a. Psoas major m.: Eighth thoracic to first sacral ver- 

 tebrae; to lesser trochanter of femur. Flexes the back and 

 flexes and rotates thigh. This is a wide flat muscle. Probe 

 but do not transect. 



65^. Psoas minor (p. parvus) m.iLast three or four lumbar 

 and sacral vertebrae; to pubis. Flexes back. This muscle 

 inserts by a narrow tendon into the ihopectineal eminence 

 (Fig. 14, IE) on the cranial border of the pubis. It is a small 

 muscle and lies mediad to the psoas major. 



