The intercostobrachial nerve is the name applied to the lateral cutaneous branch of the second intercostal nerve. It arises anterior to the

long thoracic nerve The long thoracic nerve (also: external respiratory nerve of Bell or posterior thoracic nerve) is a branch of the brachial plexus derived from cervical nerves C5-C7 that innervates the serratus anterior muscle. Structure Origin The long th ...

. It provides sensory innervation to the skin of the axilla, and a variable region of the medial side of the upper arm.

Anatomy

The lateral cutaneous branch of the second intercostal nerve does not divide like other intercostal nerves into an anterior and a posterior branch.

Course

It pierces the intercostalis externus muscle and the

serratus anterior muscle The serratus anterior is a muscle of the chest. It originates at the side of the chest from the upper 8 or 9 ribs; it inserts along the entire length of the anterior aspect of the medial border of the scapula. It is innervated by the long tho ...

, crosses the

axilla The axilla (: axillae or axillas; also known as the armpit, underarm or oxter) is the area on the human body directly under the shoulder joint. It includes the axillary space, an anatomical space within the shoulder girdle between the arm a ...

to the medial side of the arm, and joins with a filament from the

medial brachial cutaneous nerve The medial brachial cutaneous nerve (lesser internal cutaneous nerve; medial cutaneous nerve of arm) is a sensory branch of the medial cord of the brachial plexus derived from spinal nerves C8-T1. It provides sensory innervation to the medial arm. ...

. 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 The radial nerve is a nerve in the human body that supplies the posterior portion of the upper limb. It innervates the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the Posterior compartment of the ...

Relations

The size of the intercostobrachial nerve is in inverse relationship to that of the

Variation

An additional intercostobrachial nerve is frequently given off from the lateral cutaneous branch of the third intercostal nerves; it supplies filaments to the

and medial side of the arm.

Clinical significance

It is often the source of referred cardiac pain. The intercostobrachial nerve is 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.

Additional images

File:Gray811and813.PNG, Cutaneous nerves of right upper extremity. File:Gray812and814.svg, Diagram of segmental distribution of the cutaneous nerves of the right upper extremity. File:Innervation oberarm.gif, Innervation

References

External links

* - "Axillary Region: Nerves" * {{Authority control Spinal nerves Thoracic nerves