Name

# Psoas Minor

Pronunciation

(SO-us MI-nor)

Origin/Proximal Attachment

Sides of bodies of T12 & L1 vertebra

Insertion/Distal Attachment

Pubic ridge

Action/Relevance

Weak flexor of the pelvis & lumbar spine

Innervation

Ventral ramus of the first lumbar nerve

Notes

Psoas minor is one of the muscles of the posterior abdominal wall. It is absent in 30-40% of the population.

It originates from the:

* vertebral bodies of T12 and L1

* intervertebral disc between T12 and L1

Passing inferiorly and slightly laterally with a long tendon, it inserts into the:

* fascia overlying the iliopsoas muscle

* pectineal line of the pubis

* iliopubic eminence

It is innervated by the anterior primary rami of the first lumbar nerve (L1).

Psoas minor has a weak action to:

* flex the pelvis

* flex the lumbar region of the vertebral column