Relation of roots and trunks of brachial plexus to scalenus anterior muscle and its clinical significance

Variations in the structures at the root of neck are important in understanding many clinical and surgical conditions. Scalenus anterior, the key muscle in the neck, usually related to the roots of brachial plexus in its posterior aspect. This study was designed to evaluate the relations of roots of brachial plexus to the scalene muscles. Posterior triangles of neck on both sides were studied in 24 cadavers. In two cases C5 and C6 pierced scalenus anterior muscle and emerged from its anterior surface. In other specimen roots of C5, C6 and C7 entered scalenus muscle and exited anterolateraly in a sequential manner. Knowledge of such variations is important for anaesthetists and surgeons.