Disclosures: Javier F. Jusino Alamo: No financial relationships or conflicts of interest

Case Diagnosis: Two elderly cadavers with distinct intercostobrachial nerve (ICBN) anatomical variations.

Case Description or Program Description: During usual cadaveric dissection of the axillary region in the upper extremity, an anatomical variation was found in two elderly adults with abnormal branches to the ICBN. A female cadaver, on her right upper extremity, presented a bifurcation that arose from the second and third intercostal spaces before merging and forming the ICBN. On the contrary, a male donor had a trifurcation exiting the second, third and fourth intercostal spaces. This trifurcation joined the lateral cutaneous branch (LCB) of the first intercostal nerve giving rise to the ICBN. Nonetheless, both ICBN maintained their common route towards the axilla and medial side of the arm where they supply sensation to the posteromedial aspect of the upper arm.

Setting: Medicine School Human Gross and Developmental Anatomy Laboratory

Assessment/Results: Commonly, the ICBN is identified as a single trunk arising from the T2 spinal level. Here, we report ICBN variations found incidentally on cadaveric dissection of two elderly adults. As mentioned, the present study reports a bifurcation that merges to form the ICBN, and a trifurcation that joins the LCB of the first intercostal nerve to form the ICBN.

Discussion (relevance): Commonly originating from the T2 spinal level, the ICBN is a LCB of the second intercostal nerve. This nerve traverses the axilla to the medial side of the arm. Due to its course, knowledge about its anatomical variability is significant in axillary lymph node dissection for breast cancer or any other procedure that involves the axillary region. ICBN lesions are associated to postoperative pain, paresthesia, and loss of upper extremity sensation in the dermatome supplied by this nerve.

Conclusions: Reporting such ICBN variations allows surgeons to work carefully during these procedures, increasing the chance of ICBN preservation. Such preservation allows for the improvement of postoperative quality of life.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/case-report-intercostobrachial-nerve-anatomical-variations-in-two-elderly-cadavers-and-their-clinical-implications/