Psoas Major Muscle

Authors

Affiliations

Nathaniel Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Muscle	Origin	Insertion	Innervation	Action
Psoas Major	T12-L4 and associated IV discs L1-L5 TP	Lesser Trochanter	Lumbar Plexus Direct Br. L1 - L3	Hip: Flexion, ER L/S (unilateral contraction with femur fixed): I/L spine sidebend L/S (bilateral contraction): Raises trunk from supine position

Origin

• Superficial: T12–L4 and associated intervertebral disks (lateral surfaces)¹
• Deep: L1–L5 vertebrae (TPs²)
• The Psoas Major has fibrous attachments from the anterior TP of the lumbar spine as well as the anteromedial aspect of the lumbar IVD, except for L5/S1 disc²

Insertion

Femur (lesser trochanter)¹

Innervation

Lumbar plexus Direct Br. (L1, L2, L3)¹

Action

Hip joint: flexion and external rotation¹ Lumbar spine: unilateral contraction (with the femur fixed) flexes the trunk laterally to the same side; bilateral contraction raises the trunk from the supine position¹

Overview

Stretches

• 3D hip flexor stretch

References

1.

Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.

2.

Bogduk N, Pearcy M, Hadfield G. Anatomy and biomechanics of psoas major. Clinical Biomechanics. 1992;7(2):109-119. doi:10.1016/0268-0033(92)90024-X