Brachial Nerve Plexus

Human anatomy > Peripheral Nervous System > Brachial Nerve Plexus

The Brachial Nerve Plexus refers to a group of nerve fibres that run from the spine. They are formed by the anterior rami of the cervical nerve through the thoracic nerve. These nerves process to the neck, the armpit region and the arm. The Brachial plexus can be divided into different elements, and these include the division, roots, cords, and the trunks. The anterior rami is responsible for creating the roots of the brachial nerve plexus, whereas the anterior rami of the cervical nerves five and six join together to create the superior trunk. The middle trunk is comprised of cervical nerve rami 7; the inferior trunk is created through a combination of cervical nerve 8 and thoracic nerve 1. These trunks start off connected to each other; however, they eventually separate to create the anterior and posterior division.

Brachial nerve plexus

The roots created by the anterior rami come together to form the base of the trunks, and these trunks eventually branch off into different divisions. These divisions lead to cords and these cords, in turn, produce the nerve fibres that are essential for innervating the upper extremities. All these parts are essentially comprised of long fibres until they reach their final destination.

The three major roots that constitute the brachial plexus are the ones responsible for creating the five major nerves that serve the required coetaneous and muscular innervations for the upper extremities to function. The five most essential nerves of the upper extremities include the ulna nerve, the radial nerve, the axillary nerve, the median nerve, and the musculo-coetaneous nerve. The posterior cord is the one responsible for yielding the axillary nerves which, in turn, provides the shoulder joint and skin for sensory innervations. This means that the axillary nerve is responsible for the capability of the shoulder to feel pain when exerted too much. It is also the same nerve that is responsible for giving the deltoid muscles and the teres minor its sensory capabilities.

The posterior cord is the one responsible for yielding the radial nerve. The radial nerve, in turn, is responsible for the innervations in the radial portion of the forearm. The skin in the posterior receives the sensory impulses, while the motor fibres innervate the extensor muscles of the elbow’s joint. It is also the one responsible for the ability of the elbow joint to flex, whereas the supinator muscle is the one responsible for the rotational movements of the forearm and the hand. 

The function of the Brachial nerve plexus involves the muscular innervations of the upper limb, except for the trapezius muscle and the skin area near the axilla, as these areas are innervated by the intercostrobrachial nerve.

Injuries to the Brachial Plexus can occur as a result of shoulder trauma, inflammation of the upper extremities or tumours. The Parsonge-Turner syndrome causes inflammation in the brachial nerve plexus area even in the absence of injury.  The treatment for injuries of the brachial nerve plexus includes occupational and physical therapies; though in extreme cases, surgery may be necessary. Minor injuries of the brachial nerve plexus can heal by itself even without treatment.

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