The supraclavicular brachial plexus: A global review of anatomical variants and a report on Mexican cases

Background: A thorough understanding of the normal anatomy and anatomical variants of the brachial plexus is essential for safe surgical planning in the supraclavicular region. Although the classical anatomy is well documented, supraclavicular variants—particularly involving the anterior scalene muscle—may alter surgical landmarks and increase the risk of complications in plastic and reconstructive procedures. Methods: A comprehensive literature review was achieved using PubMed, Scopus, Web of Science, and ScienceDirect, covering anatomical variants of the supraclavicular portion of the brachial plexus. Additionally, 10 anatomical dissections were performed on corpses donated to the Faculty of Medicine of National Autonomous University of Mexico by Body Donation Program.Results: Anatomical variants were identified in two female cadavers. In one, the anterior ramus of C5 coursed anterior to the anterior scalene muscle unilaterally; in the other, this finding was bilateral. To our knowledge, this represents the first reported case of bilateral finding of this variant.Conclusions: Awareness of supraclavicular brachial plexus variants is crucial for surgeons performing procedures in the cervical region. The bilateral course of the C5 anterior ramus anterior to the scalene muscle highlights the need for meticulous anatomical evaluation during surgical planning. Keywords: Brachial Plexus; Supraclavicular Region; Anatomy, Cross-Sectional; Cadaver; Anatomic Variation; Peripheral Nerves; Neck Muscles