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

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

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

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

• 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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