Psoas minor muscle


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

Structure

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. Variations occur, however, and the insertion on the iliopubic eminence sometimes radiates into the iliopectineal arch.
The psoas minor is supplied by the four lumbar arteries and the lumbar branch of the iliolumbar artery.

Variation

The psoas minor is considered inconstant and is often absent, only being present in about 40% of human specimens studied. It has an average length of about 24 cm, of which about 7.1 cm is muscle tissue and about 17 cm is tendon.

Function

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

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