Human Anatomy

Brachial plexus

A network of nerves that supplies the upper limb and provides motor and sensory innervation to the shoulder, arm, and hand.

The brachial plexus is a complex network of nerves formed by the anterior rami of the spinal nerves from C5 to T1. It branches into several important nerves that control muscle movement and sensation in the upper limbs. This intricate system ensures that movements ranging from lifting to grasping are performed efficiently and effectively.

Terminologia Anatomica

plexus brachialis

System

Nervous system

Function

The primary function of the brachial plexus is to facilitate communication between the central nervous system and the muscles of the upper limb. It is responsible for both motor and sensory functions. Motor-wise, it innervates major muscle groups, enabling actions such as lifting the arm, flexing the wrist, and gripping objects. Sensory-wise, it transmits tactile sensations, temperature, and pain from the skin of the upper limb and parts of the shoulder. Disorders affecting the brachial plexus can lead to weakness, numbness, or loss of function, highlighting its essential role in day-to-day activities.

Location

Located in the neck and extending into the axilla (armpit region), the brachial plexus starts at the levels of cervical vertebrae 5 through thoracic vertebrae 1. It branches out into trunks, divisions, cords, and terminal branches. The trunks consist of three main sections: upper, middle, and lower, which then split into anterior and posterior divisions. These divisions regroup into lateral, posterior, and medial cords, from which various nerves arise to innervate different regions of the upper limb. Its strategic positioning not only allows it to regulate upper limb function but also provides a protective space within the axilla for the delicate nerves and vessels it encompasses.

Did You Know?

The brachial plexus is usually assessed clinically for injuries sustained from trauma, such as traction injuries during childbirth.
It is essential for not just motor control but also for proprioception, which helps the body understand the position of the upper limbs in space.
Anatomical variants exist, meaning that the structure and branching patterns can vary significantly between individuals, which can impact surgical approaches and nerve block procedures.