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Lateral Cutaneous Branch of Third Intercostal Nerve (Left)
Nervous System

Lateral Cutaneous Branch of Third Intercostal Nerve (Left)

Ramus cutaneus lateralis nervi intercostalis tertii

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The lateral cutaneous branch of anterior ramus of third thoracic nerve (or third intercostal nerve) arises from the anterior ramus of the third thoracic nerve roughly along the mid-axillary line.


The lateral cutaneous branch may travel for a short distance with its parent nerve (the anterior ramus) within the intercostal space. It then pierces the thoracic wall through the internal and external intercostal muscles, emerging just anterior to the serratus anterior muscle.


The lateral cutaneous branch further subdivides into anterior and posterior branches. The anterior branches extend towards the pectoralis major, while the posterior branches extend backwards towards the latissimus dorsi muscle.

Supplied Structures & Function

The lateral cutaneous branch of the third intercostal nerve (or anterior ramus of third thoracic nerve) conveys sensory innervation from the skin overlying the third intercostal space. See our dermatome map for cutaneous innervation. In some instances, a second intercostobrachial nerve arises from the lateral cutaneous branch, which also sends nerve filaments to the axilla and medial arm.

Learn more about this topic from other Elsevier products

Intercostal Nerve

ScienceDirect image

The intercostal nerve frequently runs within the middle of the intercostal space (73% of the time) and occasionally courses along the inferior aspect of the intercostal space just above the subjacent rib (Hardy, 1988).

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