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Intercostobrachial Nerve

nervus intercostobrachialis

The intercostobrachial nerve is the lateral cutaneous branch of the second intercostal nerve that crosses the axilla to supply the medial upper arm skin. It is the most commonly damaged sensory nerve during axillary lymph node dissection for breast cancer, producing the characteristic numbness and hypersensitivity of the medial upper arm and axilla that many breast cancer surgery patients experience as a long-term sequela.

Region: Upper Arm

Anatomical Data

Origin, Insertion & Supply

Origin	Lateral cutaneous branch of the second intercostal nerve (T2)

Clinical Relevance

Clinical Notes

Intercostobrachial nerve injury during axillary dissection is the most common cause of post-axillary surgery sensory symptoms, producing numbness, tingling, or allodynia over the medial upper arm and axilla that can persist for years. Nerve-sparing techniques preserving the intercostobrachial nerve reduce these symptoms significantly. The nerve is routinely sacrificed during radical axillary dissection but increasingly preserved in sentinel node procedures.

Pathology

Common Injuries & Conditions

Post-Mastectomy Pain Syndrome

Persistent medial arm and axillary pain from intercostobrachial nerve damage during axillary surgery, producing numbness and allodynia that affects quality of life in breast cancer survivors.