Upper trunk

Upper Trunk

The Upper Trunk is a significant anatomical structure in the human body, specifically within the brachial plexus. It is formed by the union of the fifth and sixth cervical nerves (C5 and C6).

Etymology[edit | edit source]

The term "trunk" in this context is derived from the Latin word "truncus," which means "the main stem of a tree or a body." This is an apt description as the upper trunk serves as a primary pathway for nerves in the upper body.

Anatomy[edit | edit source]

The upper trunk gives rise to two important branches: the suprascapular nerve and the nerve to subclavius. The suprascapular nerve innervates the supraspinatus and infraspinatus muscles, while the nerve to subclavius innervates the subclavius muscle.

Clinical Significance[edit | edit source]

Damage to the upper trunk, often due to trauma, can lead to a condition known as Erb's Palsy. This condition is characterized by weakness or paralysis of the arm, specifically the muscles innervated by the nerves arising from the upper trunk.

Related Terms[edit | edit source]

Brachial Plexus: The network of nerves that sends signals from your spine to your shoulder, arm, and hand.
Cervical Nerves: The nerves that emerge from the cervical vertebrae in the neck.
Suprascapular Nerve: A nerve that passes through the suprascapular notch and supplies the supraspinatus and infraspinatus muscles.
Nerve to Subclavius: A small nerve that arises from the upper trunk and innervates the subclavius muscle.
Erb's Palsy: A paralysis of the arm caused by injury to the upper group of the arm's main nerves.

Upper trunk Resources
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