PSOAS MINOR MUSCLE

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

• Weak trunk flexor. It flexes the trunk at the spinal joints when the pelvis is fixed.

• Laterally flexes the trunk at the spinal joints when the pelvis is fixed.

• However, because the psoas minor muscle is very close to the midline of the body, it has poor leverage for the action described above.

Antagonist
Erector spinae muscles

The psoas minor muscle is located deep in the abdomen and lies directly anterior (in front) to the psoas major muscle. It arises from the vertebral bodies and discs of the thoracic 12 and the first lumbar and is present in 60% of the population. It then inserts along the psoas major muscle in an area called the pectineal line and iliac fascia.
The psoas minor muscle mainly contributes to the iliopsoas muscle functions.