Anatomical Variations of the Median Nerve

Anatomical Variations of the Median Nerve


Introduction: The median nerve is one of the terminal branches of the brachial plexus and is formed by two roots, the lateral root from the lateral cord and the medial root from the median cord; however, several studies have shown that variations in its formation and relationships with other anatomical structures can occur.

Median nerve formation by two roots is seen in 48–88.5% of cases. Formation by three or more roots has been well documented in the literature; however, few papers have reported its incidence.

These additional roots generally arise from the lateral cord of the brachial plexus, with variation reported to range from 14.2% to 20%.

Rarely, the additional root may arise from the medial cord or the anterior division of the middle trunk of the brachial plexus.

Objectives: Variations in the morphological anatomy of the median nerve such as formation, distribution, and communication have been well documented.

All these variations should be taken into account when practicing any surgical approach for the treatment of injuries affecting the median nerve. Furthermore, they are of the utmost importance for the interpretation of the clinical presentation.

Methods: The objective of this investigation was to determine the anatomical variations in the formation of the median nerve in cadavers at the Forensic Pathology department in Central Clinical Hospital of the Academy of Sciences of the Russian Federation between January 2022 and April 2022.

A descriptive, cross-sectional, and prospective information source study was conducted on 42 anatomical bodies (corpses) and 84 brachial plexuses.

Results: After analyzing the results obtained in this investigation, we concluded that the median nerve presented variation in its formation in 22.6% of the investigated cases.

These variations were more common in males (81.8%) than females (18.2%). The anatomical variation was unilateral in 7.1% and bilateral in 19% of all anatomical bodies examined.

Conclusions: The median nerve presented a great number of variations in its formation in roughly 23% of the anatomical bodies, with males being the predominant gender.

Furthermore, the most frequent region of formation was the axillary region (92.9%). For clinicians, it is important to remember these variations during surgical procedures in this area and during the brachial plexus block.



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