Anatomy study note · Back

Deep muscles of the back

A thick column of large and small muscles in the hollow on each side of the spinous processes, from the sacrum to the skull (the postvertebral muscles, including erector spinae). Their tone keeps the normal curves of the column, because most body weight lies in front of it.

Key points

• Postvertebral column from sacrum to skull; maintain spinal curves (posture).
• Action: extension; unilaterally lateral flexion and rotation.
• Nerve: posterior rami (superficial/intermediate back muscles: anterior rami; trapezius: CN XI).
• Enclosed by the thoracolumbar fascia (3 lamellae) in the lumbar region.
• Splenius + opposite sternocleidomastoid rotate the head.
• Deep back muscles: dorsal parts of myotomes.
• Trunk muscles: from myotomes of the somites.
• Skeletal muscle: multinucleated, peripheral nuclei, striated.
• Epimysium → perimysium → endomysium.

The full note in the atlas also covers

Features · Action · Blood supply · Nerve supply · Histology · Development · Clinical notes

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Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 2, PDF pp. 150, 156–160
• Inderbir Singh’s Human Embryology, ch. 7, PDF pp. 108–109
• BRS Cell Biology & Histology, 7th ed., ch. 8, PDF pp. 135–144

More from the back

• Intervertebral discs
• Ligaments of the vertebral column
• Lumbar vertebrae
• Spinal cord
• Spinal nerves
• Suboccipital muscles
• Thoracic vertebrae
• Thoracolumbar fascia
• Vertebral column
• Atlas (C1)
• Axis (C2)
• Cervical vertebrae

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