Accessory nerve injury

The spinal cord of the accessory nerve originates from the paranuclear nucleus of the dorsal lateral of the anterior horn cell group of the spinal cord of the cervical spine 1 to 5 or 1 to 6. The fibers from this nucleus penetrate through the outer side of the spinal cord, merge into a trunk, and form a dentate Ascending between the ligament and the posterior root of the spinal nerve, it enters the skull through the occipital foramen and joins the medullary fibers. After exiting the jugular foramen, it separates from the medullary part and forms its own stem. It descends to the neck between the internal jugular veins and veins and The sternocleidomastoid muscle descends deep, and the branches dominate the sternocleidomastoid muscle. Its main trunk penetrates from the midpoint of the posterior margin of the sternocleidomastoid muscle into the posterior cervical triangle, and dives obliquely downward into the deep side of the trapezius to dominate the muscle. If the accessory nerve is injured immediately after exiting the jugular foramen, it is often injured at the same time as other nearby nerves. In the neck, the accessory nerves are superficially located across the posterior triangle of the neck, and are particularly vulnerable to injuries. Contusions and firearm injuries are relatively rare. The most common is accidental injury. When the lesion only infiltrates the medullary nucleus of the paraganglia, the symptoms are the same as when the vagus nerve is damaged, without the symptoms of neck muscles.