Subtrapezial Plexus

The combination of C3, C4, and spinal accessory nerve constitute the Subtrapezial Plexus. The subtrapezial plexus has both a motor and a sensory component. The trapezius is innervated by both the C3, C4 contribution and the spinal accessory nerve. Proprioceptive fibers for the trapezius and sternocleidomastoid muscles are conveyed by C2, C3, and C4.