INTRODUCTION: Normally the undivided lateral cutaneous branch of second intercostal nerve leaves the second intercostal space by piercing the lateral thoracic wall at midaxillary plane, passes along the base of axilla within the central group of axillary lymph nodes, reaches the upper and medial part of arm where it joins with medial cutaneous nerve of arm to form intercostobrachial nerve to supply the skin of upper and medial parts of arm.
The upper branch of 1st intercostobrachial nerve passed along the base of axilla, then left the axilla by passing through lower triangular space and finally joined with posterior cutaneous nerve of arm on each side whereas the lower branch passed along the base of axilla to reach the upper and medial part of arm where they join with medial cutaneous nerve of arm on each side.
The 1st intercostobrachial nerve joined with 2nd one to form a single trunk which passed along the base of axilla and reached the upper and medial part of arm to join with medial cutaneous nerve of arm on each side.
A second intercostobrachial nerve often branches off from the anterior part of third lateral cutaneous nerve supplying the axilla and medial side of arm.
In the present study, the intercostobrachial nerve originated from the second intercostal space was accompanied by the intercostobrachial nerves from first, third and fourth intercostal spaces of both sides.
The first intercostobrachial nerve (T1) united with second one(T2) to form a single trunk before it joined with medial cutaneous nerve of arm whereas third and fourth nerves joined with medial cutaneous branch of arm separately (Fig.
Bratschi HU, Haller U (1990) (12) found the significance of the intercostobrachial nerve in axillary lymph node excision and followed up 101 modified radical mastectomies with axillary dissection.