GROSS ANATOMY

Detailed explanation-1: -Accessory nerve. The accessory nerve provides motor function to some muscles in the neck. It controls the sternocleidomastoid and trapezius muscles that allow a person to rotate, extend, and flex the neck and shoulders.

Detailed explanation-2: -The spinal accessory nerve is the eleventh cranial nerve. It is a motor nerve (somatic motor) innervating two muscles-the sternocleidomastoid and trapezius.

Detailed explanation-3: -This nerve supplies the sternocleidomastoid and trapezius muscles, which have the following functions: Rotation of head away from the side of the contracting sternocleidomastoid muscle. Tilting of the head toward the contracting sternocleidomastoid muscle. Flexion of the neck by both sternocleidomastoid muscles.

Detailed explanation-4: -The accessory or spinal nerve has a double origin but always comes out of the jugular foramen. The jugular foramen develops embryologically from the otic capsule and the baseplate. Its spinal portion comes from a series of roots starting at C6-C7 and traveling cranially to enter in the foramen magnum.