The long thoracic nerve (also: external respiratory nerve of Bell or posterior thoracic nerve) is a branch of the brachial plexus derived from cervical nerves C5-C7 that innervates the serratus anterior muscle.

Structure

Origin

The long thoracic nerve arises from the anterior rami of cervical spinal nerves C5, C6, and C7. The root from C7 may occasionally be absent. The roots from C5 and C6 pierce through the scalenus medius, while the C7 root passes in front of the muscle.

Course and relations

The long thoracic nerve descends through the cervicoaxillary canal. It is posterior to the brachial plexus,

Function

The long thoracic nerve innervates the serratus anterior muscle. Mechanisms of injury include:

  • nerve lesions. Treating breast cancer with removal of axillary lymph nodes.
  • carrying weight, such as heavy bags, over the shoulder for a prolonged time.
  • Parsonage Turner Syndrome, an autoimmune disease.
  • trauma or infection. This is most prominent when the arm is lifted forward or when the patient pushes the outstretched arm against a wall. However, even winging may not be evident until the trapezius stretches enough to reveal an injury several weeks later.

See also

  • Backpack palsy

References

Additional images

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File:Gray809.png|The right brachial plexus (infraclavicular portion) in the axillary fossa; viewed from below and in front.

File:Brachial plexus.svg|Brachial plexus

File:Brachial_plexus_color.svg|Brachial plexus with courses of spinal nerves shown

</gallery>

  • - "The major subdivisions and terminal nerves of the brachial plexus."
  • Long Thoracic Nerve - BlueLink Anatomy - University of Michigan Medical School