Brachial

Brachial Plexus

Latin	Plexus brachialis

The brachial plexus is a complex network of nerves that originates from the spinal cord in the neck and extends through the cervical vertebrae and vertebral column to provide motor and sensory function to the arm, shoulder, and hand. This network is crucial for the movement and sensation in the upper limbs.

Structure

The brachial plexus is formed by the ventral rami (the anterior divisions) of the lower four cervical nerves (C5, C6, C7, and C8) and the first thoracic nerve (T1). It passes through the neck, the axilla (armpit), and into the arm. It is typically divided into five major parts:

• Roots: The five roots are the ventral rami of the spinal nerves C5-T1.
• Trunks: These roots converge to form three trunks: upper, middle, and lower.
• Divisions: Each trunk splits into an anterior and a posterior division.
• Cords: The divisions recombine to form three cords named according to their position relative to the axillary artery: lateral, medial, and posterior.
• Branches: Each cord gives rise to several branches which innervate various parts of the arm and shoulder.

Function

The brachial plexus primarily provides motor and sensory innervation to the upper limb. Each nerve within the plexus can be traced back to specific muscles and skin areas of the shoulder, arm, and hand. This includes control over muscle movements and the relay of sensory information such as touch, pain, and temperature.

Clinical Significance

Injury to the brachial plexus can occur due to trauma, such as motor vehicle accidents or falls, or can be a result of medical conditions like inflammation or tumors. Symptoms of a brachial plexus injury can include weakness, loss of sensation, or paralysis in the upper limb. Treatment varies depending on the severity of the injury and can range from physical therapy to surgical intervention.

See Also

• Nervous system
• Peripheral neuropathy
• Cervical vertebrae
• Thoracic vertebrae