NERVE LIBRARY · Head, neck & respiratory
Spinal accessory nerve
Spinal accessory nerve · CN XI
Shoulder droop, weak shrug or lateral scapular winging after neck surgery.
- Roots / nucleus
- Spinal accessory motor nucleus; not a single brachial root
- Function
- Motor
- 3D protocols
- Advanced localization guide
01Course and sensory territory
No cutaneous sensory supply.
02Motor supply
Trapezius and sternocleidomastoid.
03Localization clues
Shoulder droop, weak shrug or lateral scapular winging after neck surgery.
04Combine the studies
Compare trapezius CMAP/EMG with sternocleidomastoid and other scapular stabilizers.
Related muscles
Connect to a clinical question
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References and further reading
- Upper Extremity Proximal Mononeuropathies ↗AAPM&R KnowledgeNow · Society educational review · Link accessed 2026-09-08
Educational synthesis; independent neuromuscular specialist review is pending. Publication dates and compilation dates are distinct. This is an original teaching synthesis; consult the source for complete methods and criteria.