Background: Anatomical variations of the brachial plexus are common but underrecognized in medical education. Communicating branches between the musculocutaneous nerve (MCN) and median nerve (MN) have been reported in 10–54% of cases and may significantly impact regional anesthesia, surgical approaches, and electrodiagnostic interpretation. Objective: To characterize anatomical variations of the terminal branches of the brachial plexus, with emphasis on MCN–MN communications and their clinical relevance.
Methods: Cadaveric dissections were performed on 31 embalmed donors over two consecutive academic years. Upper extremities (UE) were examined bilaterally in 28 donors and unilaterally in 3 donors (total n = 55 UE). Terminal branches were dissected and evaluated for communicating branches and atypical patterns. Variations were classified using established frameworks, including the Le Minor classification, and documented with cadaveric imaging. Observed patterns were compared with existing literature.
Results: MCN–MN communicating branches were identified in 12 of 55 UE (21.8%), with consistent prevalence across cohorts (2025: 6/26, 23.1%; 2026: 6/29, 20.7%). One donor demonstrated a bilateral Type V Le Minor variation. Additional atypical lateral cord branching patterns were observed, including variants with potential implications for altered nerve course and distribution. Discussion: These variations may alter expected motor and sensory distributions, leading to atypical clinical presentations. Clinically, they may reduce the accuracy of nerve blocks, complicate electrodiagnostic interpretation, and contribute to unexpected patterns of weakness or sensory loss.
Conclusion: Brachial plexus variations are common and clinically significant. These findings demonstrate consistent prevalence across cohorts and highlight bilateral and higher-order variants, supporting improved recognition in clinical practice, procedural planning, and medical education. Limitations include small sample size and cadaveric design.
Methods: Cadaveric dissections were performed on 31 embalmed donors over two consecutive academic years. Upper extremities (UE) were examined bilaterally in 28 donors and unilaterally in 3 donors (total n = 55 UE). Terminal branches were dissected and evaluated for communicating branches and atypical patterns. Variations were classified using established frameworks, including the Le Minor classification, and documented with cadaveric imaging. Observed patterns were compared with existing literature.
Results: MCN–MN communicating branches were identified in 12 of 55 UE (21.8%), with consistent prevalence across cohorts (2025: 6/26, 23.1%; 2026: 6/29, 20.7%). One donor demonstrated a bilateral Type V Le Minor variation. Additional atypical lateral cord branching patterns were observed, including variants with potential implications for altered nerve course and distribution. Discussion: These variations may alter expected motor and sensory distributions, leading to atypical clinical presentations. Clinically, they may reduce the accuracy of nerve blocks, complicate electrodiagnostic interpretation, and contribute to unexpected patterns of weakness or sensory loss.
Conclusion: Brachial plexus variations are common and clinically significant. These findings demonstrate consistent prevalence across cohorts and highlight bilateral and higher-order variants, supporting improved recognition in clinical practice, procedural planning, and medical education. Limitations include small sample size and cadaveric design.