Brachial Plexus

Brachial Plexus
Details
From	Roots of C5-C8, T1
Innervates	Upper limb
Identifiers
Latin	Plexus brachialis
TA98
TH	{{#property:P1694}}
TE	{{#property:P1693}}
FMA	{{#property:P1402}}
Anatomical terminology

The Brachial Plexus is a network of nerves that originate from the spinal cord in the neck and travel down the arm. This plexus is responsible for the motor and sensory innervation of the entire upper limb, except for the trapezius muscle and an area of skin near the axilla.

Structure

The Brachial Plexus is formed by the anterior rami (divisions) of cervical spinal nerves C5, C6, C7, and C8, and the first thoracic spinal nerve, T1. These roots merge to form three trunks:

• Upper trunk – formed by the union of the C5 and C6 roots.
• Middle trunk – continuation of the C7 root.
• Lower trunk – formed by the union of the C8 and T1 roots.

Each trunk then splits into an anterior and a posterior division, which recombine to form three cords:

• Lateral cord – formed from the anterior divisions of the upper and middle trunks.
• Medial cord – formed from the anterior division of the lower trunk.
• Posterior cord – formed by the joining of all three posterior divisions.

These cords give rise to several major branches that provide motor and sensory functions to the shoulder, arm, forearm, and hand.

Branches

The branches of the Brachial Plexus include:

• Axillary nerve
• Musculocutaneous nerve
• Median nerve
• Ulnar nerve
• Radial nerve

Each nerve has a specific area of the arm that it innervates, contributing to movements and sensation.

Clinical Significance

Injury to the Brachial Plexus can occur due to trauma, such as from motor vehicle accidents or birth injuries. Symptoms of such injuries can include weakness or paralysis of the upper limb, loss of sensation, and severe pain.

Diagnosis and Treatment

Diagnosis of Brachial Plexus injuries involves physical examination, imaging studies such as MRI or CT scans, and sometimes nerve conduction studies. Treatment can range from physical therapy to surgical interventions, depending on the severity of the injury.

See Also

• Nerve injury
• Peripheral neuropathy
• Upper limb anatomy