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Quadratus Lumborum Muscle

Quadratus Lumborum Muscle

Author: Scott A. Sheffield MS

Last update: Nov 1st, 2022

The quadratus lumborum is a flat, four-sided muscle situated at the sides of the lumbar region of the back.

Quadratus Lumborum:

Unlabelled image of the muscles of the back.

Labelled image of the sternocleidomastoid, splenius capitis, splenius cervicis, external intercostals, and quadratus lumborum muscles as well as the iliocostalis, longissimus, and spinalis muscle groups.

Labelled image of the iliocostalis, longissimus, spinalis muscle groups, and the quadratus lumborum

Labelled image of the longissimus, spinalis muscle group, and quadratus lumborum muscle.

Labelled image of the spinalis muscle group, and quadratus lumborum muscle.

Labelled image of the semispinalis capitis, semispinalis thoracis, multifidus, and quadratus lumborum muscles

Labelled image of the multifidus, and quadratus lumborum muscles.

Labelled image of the quadratus lumborum muscle.

Muscularis Quadratus Lumborum

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Attachments of the Quadratus Lumborum: Origin & Insertion

Origin: Medial half of the posterior iliac crest and iliolumbar ligament.

Insertion: Transverse processes of L1-L4 and medial half of 12th rib.

Unlabelled image of the muscles of the back.

Labelled image of the insertion and origin of the quadratus lumborum.

Origin and insertion of the quadratus lumborum.

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Actions of the Quadratus Lumborum Muscle:

Bilateral action: extends vertebral column; stabilizes 12th rib while breathing.

Extensions of the vertebral column animation slide 1

Extensions of the vertebral column animation slide 2

Extensions of the vertebral column animation slide 3

Extensions of the vertebral column animation slide 4

Extension of the vertebral column.

Ipsilateral action: laterally flexes vertebral column.

Learn the muscles of the trunk wall quickly and efficiently thanks to this muscle anatomy reference chart for the trunk wall.

Lateral flexion of the vertebral column animation slide 1

Lateral flexion of the vertebral column animation slide 2

Lateral flexion of the vertebral column animation slide 3

Lateral flexion of the vertebral column animation slide 4

Lateral flexion of the vertebral column animation slide 5

Lateral flexion of the vertebral column.

Nerve Supply to Quadratus Lumborum:

Subcostal nerve (thoracic; T12) and ventral rami of lumbar spinal nerves (L1-L4).

Overview of the Muscles of the Back:

Test yourself image answers hidden.

Test yourself image showing answers: trapezius, deltoid, latissimus dorsi

Test yourself image showing answers: supraspinatus, infraspinatus, teres minor, teres major

Test yourself image showing answers: levetor scapula, rhomboids minor, rhomboids major, serratus anterior

Test yourself image showing answers: serratus anterior superior, serratus posterior inferior

Test yourself image showing answers: Sternocleidomastoid, splenius capitis, splenius cervicis, external intercostals, iliocostalis group, longissimus group, quadratus lumborum, spinalis group

Test yourself image showing answers: Iliocostalis group, Longissimus group, spinalis group, quadratus lumborum

Test yourself image showing answers: Longissimus group, Spinalis group, Quadratus lumborum

Test yourself image showing answers: Spinalis group, quadratus lumborum

Test yourself image showing answers: semispinalis capitis, semispinalis thoracis, multifidus, quadratus lumborum

Test yourself image showing answers: multifidus, quadratus lumborum

Test yourself image showing answers: quadratus lumborum

Test yourself image showing answers: insertion and origin

Review the muscles of the back and test yourself.

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