Anatomical Variation in the Formation of the Median Nerve With Triple and Quadruple Roots of Origin: A Cadaveric Case Report

TL;DR

This paper reports a rare anatomical variation in the formation of the median nerve with three and four roots in a single cadaver.

Contribution

The study documents a rare bilateral and asymmetric median nerve formation with triple and quadruple roots in the same individual.

Findings

A 72-year-old female cadaver exhibited a median nerve with three roots on the left and four roots on the right.

The variant roots merged anterior to the third part of the axillary artery bilaterally.

Such anatomical variations may impact surgical procedures and nerve blocks.

Abstract

The brachial plexus demonstrates a wide range of anatomical variations, many of which carry significant implications for clinical practice. Conventionally, the median nerve arises from two roots: a lateral root from the lateral cord and a medial root from the medial cord. During the routine dissection of a 72-year-old female cadaver, an unusual bilateral but asymmetric anomaly was observed. On the left side, the median nerve was formed by three roots, while on the right, it was formed by four roots. In both axillae, the variant roots united anterior to the third part of the axillary artery. No additional plexus abnormalities were present. The coexistence of triple and quadruple roots in the same individual is exceptionally rare. These variations may complicate axillary surgeries, reduce the reliability of brachial plexus blocks, and predispose to unexpected neurological deficits. Recognition of such anomalies is essential for surgeons, anesthesiologists, neurologists, and anatomists.

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