brachial plexus

(noun)

A network of nerve fibers, running from the spine, formed by the ventral rami of the lower four cervical and first thoracic nerve roots (C5–C8, T1). It proceeds through the neck, the axilla (armpit region), and into the arm. It also supplies the brachium, the antebrachium, and the hand.

Related Terms

Examples of brachial plexus in the following topics:

  • Brachial Plexus

    • The brachial plexus is formed by the four lower cervical spinal nerves and the first thoracic spinal nerve.
    • The brachial plexus proceeds through the neck, the axilla (armpit region), and into the arm.
    • Lesions on the brachial plexus can lead to severe functional impairment.
    • The brachial plexus is divided into roots, trunks, divisions, cords, and branches.
    • The right brachial plexus with its short branches, viewed from the front.

  • Injuries to Nerves Emerging from the Brachial Plexus

    • Brachial plexus injuries, or lesions, are caused by damage to those nerves.
    • Brachial plexus injuries can occur as a result of shoulder trauma, tumours, or inflammation.
    • But in general, brachial plexus lesions can be classified as either traumatic or obstetric.
    • Although injuries can occur at any time, many brachial plexus injuries happen during birth: the baby's shoulders may become impacted during the birth process causing the brachial plexus nerves to stretch or tear.
    • Describe the effects of injuries to the nerves of the brachial plexus

  • Plexuses

    • The brachial plexus is formed by the ventral rami of C5–C8 and the T1 spinal nerves, and lower and upper halves of the C4 and T2 spinal nerves.
    • The plexus extends toward the armpit (axilla).
    • The lumbar plexus is formed by the ventral rami of L1–L5 spinal nerves with a contribution of T12 form the lumbar plexus.
    • In addition, the celiac plexus serves the internal organs, and Auerbach's plexus serves the gastrointestinal tract.
    • Cervical (C5–C8) and thoracic (T1) nerves comprise the brachial plexus, which is a nerve plexus that provides sensory and motor function to the shoulders and upper limbs.

  • Intercostal Nerves

    • They differ from the anterior divisions of the other spinal nerves in that each pursues an independent course without plexus formation.
    • The larger branch leaves the thorax in front of the neck of the first rib and enters the brachial plexus.
    • The branch from the second nerve unites with the anterior supraclavicular nerves of the cervical plexus.

  • Function and Physiology of the Spinal Nerves

    • The last four cervical spinal nerves, C5 through C8, and the first thoracic spinal nerve, T1, combine to form the brachial plexus, or plexus brachialis, a tangled array of nerves, splitting, combining and recombining to form the nerves that subserve the upper limb region and upper back.
    • Although the brachial plexus may appear tangled, it is highly organized and predictable with little variation among people.
    • The anterior divisions of the lumbar, sacral, and coccygeal nerves form the lumbosacral plexus, the first lumbar nerve being frequently joined by a branch from the twelfth thoracic.
    • For descriptive purposes, this plexus is usually divided into three parts: lumbar plexus, sacral plexus, and pudendal plexus.

  • Overview of the Spinal Nerves

    • The anterior distribution includes the cervical plexus (C1–C4) and brachial plexus (C5–T1).
    • A loop of nerves called ansa cervicalis is also part of the cervical plexus.
    • The first three and the greater part of the fourth are connected by anastomotic loops and form the lumbar plexus.
    • The smaller part of the fourth joins with the fifth to form the lumbosacral trunk, which assists in the formation of the sacral plexus.
    • Its anterior root helps form the coccygeal plexus.

  • Branches of Spinal Nerves

    • Some ventral rami merge with adjacent ventral rami to form a nerve plexus, a network of interconnecting nerves.
    • Nerves emerging from a plexus contain fibers from various spinal nerves, which are now carried together to some target location.
    • Major plexuses include the cervical, brachial, lumbar, and sacral plexuses.

  • Sacral and Coccygeal Plexuses

    • The sacral plexus is the plexus of the three sacral spinal nerves (S2–S4) that arise from the lower back just above the sacrum.
    • The sacral plexus is a nerve plexus that provides motor and sensory nerves for the posterior thigh, most of the lower leg, the entire foot, and part of the pelvis.
    • Often, the sacral plexus and the lumbar plexus are considered to be one large nerve plexus, the lumbosacral plexus.
    • The coccygeal plexus originates from the S4, S5, and Co1 spinal nerves.
    • It is interconnected with the lower part of the sacral plexus.

  • Autonomic Plexuses

    • The autonomic plexuses include the cardiac plexus, the pulmonary plexus, the esophageal plexus, and abdominal aortic plexus, and the superior and inferior hypogastric plexuses.
    • The cardiac plexus is a plexus of nerves situated at the base of the heart that innervates the heart.
    • The pulmonary plexus is an autonomic plexus formed from pulmonary branches of vagus nerve and the sympathetic trunk.
    • The esophageal plexus and the cardiac plexus contain the same types of fibers and are both considered thoracic autonomic plexus(es).
    • The inferior hypogastric plexus (pelvic plexus in some texts) is a plexus of nerves that supplies the viscera of the pelvic cavity.

  • Cervical Plexus

    • The cervical plexus is the plexus of the ventral rami of the first four cervical spinal nerves.
    • The cervical plexus is a plexus of the ventral rami of the first four cervical spinal nerves located from the C1 to C4 cervical segment in the neck.
    • Nerves formed from the cervical plexus innervate the back of the head, as well as some neck muscles.
    • The cervical plexus has two types of branches: cutaneous and muscular.
    • The great auricular nerve originates from the cervical plexus and is composed of branches from spinal nerves C2 and C3.