Iliocostalis Lumborum

Original Editor - Oyemi Sillo

Lead Editors - Vidya Acharya, Oyemi Sillo, Kim Jackson, Abbey Wright, Lucinda hampton, Evan Thomas, WikiSysop and 127.0.0.1  

Description

Iliocostalis Lumborum belongs to the lateral column of the Sacrospinalis group of muscles. 

Origin

Anterior surface of a broad and thick tendon w attached to the medial crest of sacrum, spinous processes of the lumbar vertebrae, 11th and 12th thoracic vertebrae, posterior part of the medial lip of iliac crest, supra-spinous ligament and the lateral crest of sacrum.

Insertion

By tendons into inferior borders of the angles of the lower 6 or 7 ribs

Nerve Supply

Dorsal rami of thoracic and lumbar spinal nerves (T7 to L3)

Blood Supply

Dorsal branches of the lumbar arteries from the aorta. Dorsal branches of the lateral sacral artery from the internal iliac artery.

Action

• acting bilaterally, extension and hyperextension of the spine
• acting unilaterally, laterally flexes the spine
• assists as an accessory muscle of expiration, due to its insertion on the ribs.

Function

postural stabilization of vertebral column

Assessment

Power

Position: Prone with hands clasped behind buttocks or head.

Fixation: Examiner must stabilize the legs firmly on the table.

Test: Trunk extension

Pressure: If performed with hands behind back no pressure is needed.

Weakness

Bilateral weakness of low back muscles results in a lumbar kyphosis and increased thoracic kyphosis.

Unilateral weakness results in lateral curvature with convexity towards the weak side.

Length

Bilateral contracture of low back muscles results in lordosis.

Unilateral contracture results in scoliosis with convexity to the opposite side.