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Stretch-induced spinal accessory nerve palsy
E L Logigian1, J M McInnes, A R Berger
1Clinical Neurophysiology Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston.
Muscle & Nerve
|February 1, 1988
Summary
Sudden head turning with heavy objects caused left spinal accessory nerve palsy. Electrophysiology revealed partial and complete nerve damage, affecting key shoulder and neck muscles.
Area of Science:
- Neurology
- Anatomy
- Physiology
Background:
- Spinal accessory nerve (SAN) palsy can result from various injuries.
- Understanding the specific nerve branches and their functions is crucial for diagnosis and treatment.
Observation:
- A young man developed left SAN palsy after rapidly turning his head right while carrying heavy objects.
- This action subjected the neck and shoulder structures to significant mechanical stress.
Findings:
- Electrophysiologic studies indicated partial axonotmesis in SAN branches supplying the sternocleidomastoid and upper/middle trapezius.
- Complete axonotmesis was observed in branches to the lower trapezius.
- A minor cervical plexus contribution to lower trapezius innervation was noted.
Implications:
- This case highlights a potential mechanism for acute SAN injury due to combined head and shoulder movement.
- The findings underscore the differential vulnerability of SAN branches to traction injuries.
- Knowledge of accessory and cervical plexus innervation is important for evaluating trapezius function post-injury.