Intercostobrachial nerve

The lateral cutaneous branch of the second intercostal nerve does not divide, like the others, into an anterior and a posterior branch; it is named the intercostobrachial nerve. It pierces the Intercostalis externus and the Serratus anterior, crosses the axilla to the medial side of the arm, and joins with a filament from the medial brachial cutaneous nerve. It then pierces the fascia, and supplies the skin of the upper half of the medial and posterior part of the arm, communicating with the posterior brachial cutaneous branch of the radial nerve. It is often the source of referred cardiac pain.

The intercostabrachial nerve is also sometimes divided in axillary node clearance (ANC), such as that done for breast cancer surgery which requires the removal of the axillary nodes. Sensation to the cutaneous region supplied by the nerve is affected.

The size of the intercostobrachial nerve is in inverse relationship to that of the medial brachial cutaneous nerve.

A second intercostobrachial nerve is frequently given off from the lateral cutaneous branch of the third intercostal; it supplies filaments to the axilla and medial side of the arm.

• Cutaneous innervation of the upper limbs

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  Cutaneous nerves of right upper extremity.
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  Diagram of segmental distribution of the cutaneous nerves of the right upper extremity.
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  Innervation

This article incorporates text in the public domain from page 946 of the 20th edition of Gray's Anatomy (1918)

• Anatomy photo:05:st-0505 at the SUNY Downstate Medical Center - "Axillary Region: Nerves"
• Hand kinesiology at the University of Kansas Medical Center