ANATOMICAL STUDY OF THE RELATIONSHIP BETWEEN THE MEDIAN NERVE AND LINES DRAWN ON THE PALM OF THE HAND

Abstract

On the palmar surface of the hand, there are reference lines that help locate deep structures and prevent injuries during surgeries. The main one, the Kaplan’s Cardinal Line (KCL), described in 1953 and redefined in 1968, extends from the crease between the thumb and index finger toward the ulnar border of the hand. It is used together with the A1 line to guide incisions and identify structures such as the median nerve, ulnar nerve, superficial palmar arch, and transverse carpal ligament. The present study aims to describe and correlate, through dissections, the anatomy and variations of the median nerve in relation to these palmar lines, comparing the findings with the medical literature in order to assist surgeons in their clinical practice. Our results showed positional variations of the motor branch relative to the A1 and KCL lines. When compared with studies found in the literature, our findings are consistent regarding the KCL line but differ concerning the positioning of the nerve in relation to the A1 line.

DOI: https://doi.org/10.56238/sevened2025.037-020