Accessory nerve

The accessory nerve is the eleventh cranial nerve. All twelve cranial nerves, the accessory nerve included, emerge from or enter the skull (the cranium) as opposed to the spinal nerves which emerge from the vertebral column. The accessory is so-called because, although it arises in the brain, it receives an additional (accessory) root from the upper part of the spinal cord. The accessory nerve supplies the sternocleidomastoid and trapezius muscles. The sternocleidomastoid muscle is in the front of the neck and turns the head. The trapezius muscle moves the scapula (the wingbone), turns the face to the opposite side, and helps pull the head back. Damage to the accessory nerve can be isolated (confined to the accessory nerve) or it may also involve the ninth and tenth cranial nerves which exit through the same opening (foramen) from the skull . Accessory neuropathy (nerve disease) can sometimes occur and recur for unknown reasons. Most patients recover. Paralysis of the accessory nerve prevents rotation of the head away from that side and causes drooping of the shoulder.

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accessory nerve n either of a pair of motor nerves that are the 11th cranial nerves, arise from the medulla and the upper part of the spinal cord, and supply chiefly the pharynx and muscles of the upper chest, back, and shoulders called also accessorius, accessory, spinal accessory nerve

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(spinal accessory nerve)

the eleventh cranial nerves (XI), which arises from two roots, cranial and spinal. Fibres from the cranial root travel with the nerve for only a short distance before branching to join the vagus and then forming the recurrent laryngeal nerve, which supplies the internal laryngeal muscles. Fibres from the spinal root supply the sternomastoid and trapezius muscles, in the neck region (front and back).

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accessory nerve, spinal nervus accessorius.