Thoracodorsal nerve

Thoracodorsal nerve is a nerve in the human body that originates from the brachial plexus, specifically the posterior cord. It is also known as the middle subscapular nerve or the long subscapular nerve. The thoracodorsal nerve innervates the latissimus dorsi muscle, which is a large muscle on the back that extends to the sides and behind the arm.

Etymology

The term "thoracodorsal" is derived from the Greek words "thorax", meaning chest, and "dorsal", meaning back. This is in reference to the nerve's location and the area it innervates.

Anatomy

The thoracodorsal nerve originates from the brachial plexus, specifically from the posterior cord. It is composed of fibers from the sixth, seventh, and eighth cervical nerves (C6, C7, C8). The nerve descends along the posterior wall of the axilla and gives off several branches to the latissimus dorsi muscle.

Function

The primary function of the thoracodorsal nerve is to innervate the latissimus dorsi muscle. This muscle is responsible for extension, adduction, transverse extension also known as horizontal abduction, flexion from an extended position, and (medial) internal rotation of the shoulder joint. It also has a synergistic role in extension and lateral flexion of the lumbar spine.

Clinical significance

Damage to the thoracodorsal nerve can result in weakness or inability to draw the arm downward and backward (as in pulling or rowing movements). This condition is known as latissimus dorsi muscle weakness.

See also

• Brachial plexus
• Latissimus dorsi muscle
• Nerve injury

References

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  Thoracodorsal nerve anatomy
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  Latissimus dorsi muscle
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  Brachial plexus diagram
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  Thoracodorsal nerve pathway
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  Colored brachial plexus