Aim:The plexus brachialis is a complex structure with anatomical variations and connections with neighboring tissues. These variations may cause disparity in the motor and sensorial innervations of the upper extremity. The knowledge of anatomy and probable variations are important for performing surgical procedures in the neck, shoulder and axilla. This study was planned to demonstrate the anatomical variations of infantile brachial plexus.Material and Methods:A total of 20 plexus brachialis from 11 fetal cadavers were dissected and examined microscopically. The branching patterns and variations were evaluated. The width of the nerves was assessed at the level of the nerve root, trunk and cord on the basis of all brachial plexuses and they were arranged in terms of thickness.Results:Half of the brachial plexuses were found to be prefıxed, while 15% were found to be postfixed. Truncus superior, medial cord and nervus ulnaris were found in normal formation, whereas anatomical variations were detected in the rest of the structures. The plexus brachialis elements were arranged in the following order from large to small according to their average thicknesses: C7 > C6 > C8 > C5 = T1; TS > TI > TM; PC > LC > MC.Conclusion:Since the risk of injury for variated branches is higher, understanding the anatomical variations of plexus brachialis and its extensions are significant importance during surgical intervention.