The accessory nerve has both cranial and spinal components. The cranial portion (cranial nerve XI), which arises from the nucleus ambiguus in the medulla oblongata, first joins the spinal accessory and then separates to join the vagus nerve. The spinal component arises from C1–C5, ascends through the foramen magnum, and then descends through the jugular foramen. It supplies the sternocleidomastoid and trapezius. It is usually spared in brachial plexus injuries and can be used as a donor. It is frequently injured in surgeries in the posterior triangle of the neck causing a winged scapula.