Actions Weak trunk flexor Latin Musculus psoas minor | Antagonist Gluteus maximus | |
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Origin Lateral surface bodies of T12 and L1 vertebrae and intervening intervertebral disc Insertion Pectineal line and iliopubic eminence Nerve Anterior ramus of nerve L1 | ||
The psoas minor is a long, slender skeletal muscle which, when present, is located anterior to the psoas major muscle.
Contents
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.
Morphology
The psoas minor is considered inconstant and is often absent, only being present in about 27% of human specimens studied. It has an average length of about 24cm, of which about 7.1cm is muscle tissue and about 17cm is tendon.
Function
The psoas minor is a weak flexor of the lumbar vertebral column.