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brachial plexus

A major nerve plexus, formed within the axilla (after it has crossed the 1st rib). They are named for their position relative to the axillary artery to which they run parallel. The brachial plexus is divided into supraclavicicular & infraclavicicular parts by the clavicle. Origin: - ventral rami of C5- C8 & T1 Location: posterior triangle Course: Rootlets that emerge from the dorsal & ventral surfaces of the spinal cord converge to form the dorsal & ventral roots of the spinal nerves. The spinal nerve divides into small dorsal ramus & large ventral ramus. The 5 ventral rami unite to form three trunks:- - Superior trunk - from C5 & C6 roots. - Middle trunk - a continuation of C7 root. - Inferior trunk - from C8 & T1 roots. Innervation: - upper limb & shoulder Structure: Each trunk divides into 2 divisions as the plexus pass posterior to the clavicle (through the cervicoaxillary canal). - Anterior division-> for the anterior aspect of the limb - Posterior division-> for the posterior aspect of the limb. 6 divisions of the brachial plexus form 3 cords:- 1) lateral cord (from the anterior division of the superior & middle trunk) a) musculocutaneous nerve |2 major nerves b) lateral root of median nerve | Additionally: lateral pectoral nerve -> receive fibers from C5-C7 2) medial cord (from the anterior division of the inferior trunk) a) ulnar nerve |2 major nerves b) medial root of median nerve | Other nerves: medial pectoral nerve, medial brachial cutaneous nerve & medial antebrachial cutaneous nerve all receive fibers from C8 & T1. 3) posterior cord (from the posterior division of all three trunks) a) radial nerve |2 major nerves b) axillary nerve | Other nerves: upper & lower subscapular nerve -> receive fibers from C5 & C6, thoracodorsal nerve -> receive fibers from C6-C8 .The cords give rise to the peripheral nerves of the upper limb.

Related

Dejerine-Klumpke palsy Erb's palsy (brachial plexus injury) Erb-Duchenne palsy; congenital brachial plexus injury

General

plexus peripheral nerve

References

  1. Stedman's Medical Dictionary 27th ed, Williams & Wilkins, Baltimore, 1999.
  2. Clinically Oriented Anatomy, 4th edition, KL Moore & AF Dalley (eds), Lippincott Williams & Wilkins, Philadelphia, PA 1999.

Component-of

axilla

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