OVERVIEW
Key Points:
• Examination of this nerve involves testing the skin along the lateral cutaneous aspect of the arm for sensation. This nerve is noted as a sensory branch of the axillary.
Sensory Innervation:
• Provides sensation to the superior lateral cutaneous aspect of the arm.
• Originates from roots C5, C6 and branches from the axillary nerve.
Nerve Transfers: This nerve can be reinnervated during procedures involving this nerve and nerve transfers.
EXAMINATION
Sensory examination includes testing the superior lateral sensory territory of the shoulder innervated by the superior lateral cutaneous nerve.
Sensory Examination:
• Ask patients to draw area of diminished sensation/numbness on a body diagram.
• Test the skin along the superior lateral aspect of the shoulder for reduced/absent sensation by use of light touch or other sensory examination modalities and compare to the other arm.
Clinical Relevance:
• Provides sensation to the superior lateral aspect of the shoulder.
• This nerve branches from the axillary nerve. Injury to the axillary nerve or to this specific nerve directly results in patients reporting reduced sensation along this territory. Patients find that loss of sensation in this territory is irritating because they can’t feel when they are tapped on the shoulder.
• Therefore this nerve function can be restored during nerve transfer to reinnervate the axillary nerve. This can be done through direct end-to-side coaptation to the lateral (sensory) side of the radial nerve to provide rudimentary sensory via nerve transfer.
• When doing motor nerve transfers to the axillary nerve, the SLC should be separated from the axillary motor components to allow the recipient motor nerves be innervated by their correct donor motor modality. This nerve can be confused with a deltoid branch as the nerve can course and pierce the middle deltoid to innervate the skin. A tug test will help discriminate this nerve’s attachment to the skin and from the deltoid branches.
Adjacent Sensory Distribution:
PROXIMAL – Supraclavicular nerve.
DISTAL/ANTERIOR – Medial brachial cutaneous.
DISTAL/POSTERIOR – Posterior brachial cutaneous.
Relevant Anatomy:
Innervation:
• Roots: C5, C6.
• Nerve: Axillary nerve.
• Sensory Territory: Superior lateral aspect of the shoulder.
• Innervation Route: C5, C6 → axillary nerve → superior lateral cutaneous nerve.
Course: The superior lateral cutaneous nerve branches from the axillary nerve at the same point where the anterior, middle, and posterior deltoid branches divide to innervate the corresponding muscles. This nerve then pierces the middle deltoid to innervate the superior lateral aspect of the shoulder.