Absence of Middle Trunk of Brachial Plexus: An Uncommon Variation

Abstract

During routine dissection of a middle aged male cadaver, it was found that the middle trunk of brachial plexus was missing on left side. The Upper trunk was formed from union of C5, C6 and C7 while the lower trunk was normal having union of C8 and T1. Rest of the plexus below cord and on right side was normal. Erb's point was present there having fibres of C5, 6&7. Knowledge of Variation in brachial plexus is very important for orthopaedic surgeons, neurosurgeon and anesthesiologists.

A Brachial Plexus with an Aberrant Middle Trunk: A Rare Anomaly

“…Upper trunk formation by ventral rami of the C5, C6, and C7 roots with subsequent absence of middle trunk has been found in four cases. 3 4 5 While a very few cases in the past have reported the absence of middle trunk along with inferior trunk formation from lower three roots. 6 7…”