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Psoas major

Region

Origin & Insertion

['Origin: T12–L5 vertebral bodies and transverse processes', 'Insertion: Lesser trochanter of femur']

Synergistic Muscles

['Iliacus', 'Rectus femoris']

Joints

['Lumbar spine', 'Hip']

Primary Actions

['Hip flexion', 'Trunk flexion']

Nerve & Spinal Segment

Direct branches from L1–L3 spinal nerves

Lumbar plexus; L1–L3

Interesting

Only muscle connecting spine to femur. [Clinically Oriented Anatomy]

Reversal of Action

Pull lumbar spine toward femur

Common Dysfunctions

Low back compression, anterior hip snapping

How to Stretch

Kneeling hip flexor stretch with reach up.

Trigger Points

How to Strengthen

Weighted leg raises.

Concentric Action

Hip flexion and external rotation

Applications:

Influences lumbar spine and pelvic alignment; rehab for LBP

Eccentric Action

Controlled leg lowering from flexed position

Isotonic Action

Leg lifts, resisted hip flexion

Related Conditions

['Anterior pelvic tilt', 'Back pain']

Isometric Action

Hold hip flexed while seated upright

Exercise Ideas

['Bridge march', 'Seated knee lifts', 'Toe taps']

Spry Juncture, LLC

How to Evolve Gracefully