Psoas minor m.

The psoas minor is a long, slender skeletal muscle which, when present, is located anterior to the psoas major muscle.

The psoas minor is a weak flexor of the lumbar vertebral column. 

Psoas minor originates from the vertical fascicles inserted on the last thoracic and first lumbar vertebrae. From there, it passes down onto the medial border of the psoas major, and is inserted to the innominate line and the iliopectineal eminence. Additionally, it attaches to and stretches the deep surface of the iliac fascia and, occasionally, its lowermost fibers reach the inguinal ligament.