Variations in the Terminal Branches of the Brachial Plexus in the Axillary Fossa

Background: The brachial plexus is the primary nerve source for the upper limb. Variations in its anatomy can alter the nerve supply to the upper extremity. Such deviations are clinically important, as they can change the symptomatology of various pathologic conditions, leading to misdiagnosis, inadequate treatment, and surgical failures as a consequence. Materials and Methods: The upper limbs of 16 human cadavers (32 extremities) were dissected at the Department of Anatomy, Histology and Embryology, Medical University-Plovdiv, Bulgaria. Eight cadavers were male and eight female, with age ranging 40-95 years (mean age: 72.63 years). Results: Three variations (18.8%) were identified unilaterally, exclusively in male cadavers; however, no statistically significant sex-based distribution was observed. The first variation involved a communicating branch between the musculocutaneous nerve and median nerve. The second was a high bifurcation of the radial nerve in the axillary fossa into two divisions. The third one was a communicating branch between the axillary nerve and the radial nerve, forming a loop beneath the subscapular artery. Conclusion: Our study identified greater variability in the branches of the posterior cord compared to the existing literature. These variations must be taken under clinical consideration to prevent diagnostic, therapeutic, and surgical errors.