A Study on the Variations in the Formation of the Trunks of Brachial Plexus

brachial plexus shows several variations in its formation and branching pattern. variations in the formation of the trunks are very rare. we studied 44 dissected specimens specifically for variations in the formation of the trunks of the brachial plexus. 5 cadavers (11.3%) showed variations in the formation of the trunks. all the variations were unilateral. in one cadaver (2.27%), the middle trunk was formed by union of c7 and c8 roots and lower trunk was formed by t1 root. upper and middle trunks were fused with each other in one specimen (2.27%). in 3 specimen (6.81%), the c5 root pierced scalenus anterior before joining c6 to form the upper trunk. knowledge of its variations is of importance to orthopedic surgeons, neurologists and anesthesiologists.