Nerve Imaging Atlas Publications Credits Contact Us Lab Home
Vagus (X)
Spinal Accessory Nerve (XI)
Cervical Plexus (C2-4)
Brachial Plexus (C5-T1)
Musculocutaneous
Radial
Median
Ulnar
Ilioinguinal / Iliohypogastric
Femoral
Sciatic
Common Peroneal
Tibial
Sural
 

 

The Spinal Accessory Nerve (Cranial Nerve XI)

The spinal accessory nerve (cranial nerve XI) provides motor innervation of the sternocleidomastoid and trapezius muscles with essentially no sensory component. The nerve emerges under the sternocleidomastoid muscle to lie on the levator scapulae and middle scalene muscles ventral to the anterior border of the trapezius muscle. Variations in the course and surface landmarks of the nerve have led investigators to study its sonographic anatomy. Because of its superficial location near lymph nodes, the spinal accessory nerve can be injured during cervical lymph node biopsy.

The spinal accessory nerve is among the smallest nerves imaged with ultrasound, with a transverse diameter of about one mm and monofascicular in sonographic appearance (Video 768 KB).

 
 
   
 

(Roll cursor over image to see labels.)  

References

Bodner G, Harpf C, Gardetto A, Kovacs P, Gruber H, Peer S, Mallhoui A. Ultrasonography of the accessory nerve: normal and pathologic findings in cadavers and patients with iatrogenic accessory nerve palsy. J Ultrasound Med. 2002 Oct;21(10):1159-63. PMID: 12369671