Superior lateral cutaneous nerve of arm

The superior lateral cutaneous nerve of the arm is a sensory nerve that provides innervation to the skin over the lower part of the deltoid muscle and the lateral side of the arm. It is a branch of the axillary nerve, which is itself a branch of the posterior cord of the brachial plexus.

Anatomy

The superior lateral cutaneous nerve of the arm arises from the axillary nerve, which exits the posterior cord of the brachial plexus. The axillary nerve travels through the quadrangular space, accompanied by the posterior circumflex humeral artery, and innervates the deltoid and teres minor muscles. After innervating these muscles, the axillary nerve continues as the superior lateral cutaneous nerve of the arm.

The nerve emerges from beneath the deltoid muscle and becomes superficial, providing sensory innervation to the skin over the lower part of the deltoid muscle and the lateral aspect of the arm. This area is often referred to as the "regimental badge" area due to its location.

Function

The primary function of the superior lateral cutaneous nerve of the arm is to convey sensory information from the skin in its area of distribution to the central nervous system. This includes sensations such as touch, pain, and temperature.

Clinical significance

Injury to the axillary nerve, such as from shoulder dislocation or surgical procedures, can lead to loss of sensation in the area supplied by the superior lateral cutaneous nerve of the arm. This can result in numbness or a tingling sensation over the "regimental badge" area.

Also see

• Axillary nerve
• Brachial plexus
• Cutaneous innervation of the upper limb
• Deltoid muscle

References

• Gray's Anatomy (public domain text)