THE INNERVATION OF THE TRAPEZIUS MUSCLE - A CERVICAL MOTOR SUPPLY

Controversy surrounds the nerve supply to the trapezius muscle. Anatom ical studies hale revealed independent connections from the C3 and C3 roots of the cervical plexus directly to the trapezius muscle. The obj ective of this study was to determine if these nerve bundles contain m otor fibres and thus constitute an additional motor supply to trapeziu s. From a study of 32 cadavers. a representative example was chosen. U sing a high powered operating microscope it was seen that such fibres were traceable to the ventral roots of the spinal cord. It is generall y accepted that fibres in the ventral roots of the spinal cord are mot or and thus, in this specimen, the trapezius muscle appeared to receiv e a direct motor supply from the cervical plexus independent of the ac cessory nerve.