Long thoracic nerve

Template:Short description Template:Use American English Template:Use mdy dates Template:Infobox nerve 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.<ref name=":0">Template:Citation</ref><ref name=":1">Template:Citation</ref><ref name=":2">Template:Citation</ref> The root from C7 may occasionally be absent.<ref name=":3">Template:Citation</ref> The roots from C5 and C6 pierce through the scalenus medius, while the C7 root passes in front of the muscle.Template:Citation needed

Course and relations

The long thoracic nerve descends through the cervicoaxillary canal. It is posterior to the brachial plexus,<ref name=":2" /> and the axillary artery and vein.<ref name=":3" /> This takes it deep to the clavicle.<ref name=":1" /> It rests on the outer surface of the serratus anterior muscle. It extends along the side of the thorax to the lower border of the serratus anterior muscle, supplying fibres to each of the muscle's digitations.<ref name=":4">Fischer, J. (2012). Anatomy of the Axilla. Fischer's Mastery of Surgery, 2 Volume Set. Retrieved September 20, 2015 from http://www.r2library.com/Resource/Title/1608317404/ch0046s1193</ref><ref name="Bertelli2005">Template:Cite journal</ref>

Function

The long thoracic nerve innervates the serratus anterior muscle.<ref name=":0" /> It supplies filaments to each of its digitations (finger-like projections).<ref name=":4" /><ref name="Bertelli2005" />

Clinical significance

Due to its long, relatively superficial course, the long thoracic nerve is susceptible to injury, either through direct trauma or stretch.<ref>Template:Citation</ref> Mechanisms of injury include:

• nerve lesions.<ref name=":2" />
• various sports injuries, typically occurring from a blow to the ribs underneath an outstretched arm.
• surgery for shoulder and thorax.<ref name="MILITARY">Template:Cite journal</ref> Treating breast cancer with removal of axillary lymph nodes.<ref>Template:Cite journal</ref>
• carrying weight, such as heavy bags, over the shoulder for a prolonged time.<ref>Template:Cite journal</ref>
• Parsonage Turner Syndrome, an autoimmune disease.<ref>Template:Cite journal</ref>
• trauma or infection.<ref name="MILITARY" />

Symptoms are often minimal – if symptomatic, a posterior shoulder or scapular burning type of pain may be reported. Some injuries, particularly lesions, can paralyse the serratus anterior muscle to produce a winged scapula.<ref name=":2" /><ref>Template:Cite journal</ref> 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.<ref>Template:Citation</ref>

See also

• Backpack palsy

Additional images

• 
  The right brachial plexus (infraclavicular portion) in the axillary fossa; viewed from below and in front.
• 
  Brachial plexus
• 
  Brachial plexus with courses of spinal nerves shown

External links

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