Equis ISSN 2398-2977

Suprascapular nerve: paralysis

Synonym(s): Sweeney

Contributor(s): Steve Adair, Caroline Hahn

Introduction

  • Suprascapular nerve injuries are relatively common; some regeneration of peripheral nerves occurs but is slow.
  • See also peripheral nerve injury   Peripheral nerve: trauma  .
  • Cause: trauma to the cranial aspect of shoulder.
  • Signs: prominent scapular spine due to atrophy of the supraspinatus and infraspinatus muscles, and lateral deviation of shoulder joint while weightbearing.
  • Diagnosis: clinical signs and neurologic/electromyographic examination.
  • Treatment: confinement and rest are crucial to prevent further damage. Surgical relief may be necessary.
  • Prognosis: depends upon extent of damage to nerve.

Pathogenesis

Etiology

  • Fractures of neck of scapula or scapular tuberosity.
  • Blows to front of shoulder.
  • Extremes of movement, especially caudal extension of shoulder.
  • Once damage initiated (even if slight) further shoulder movement, especially sudden outward excursions, may perpetuate the damage to the nerve.

Pathophysiology

  • Suprascapular nerve winds around cranial edge of scapula and is prone to stretching/bruising.
  • Damage to nerve may be mild   →   neuropraxia (temporary impairment of function); or severe   →   neurotmesis (possibly permanent).
  • Denervation atrophy of supraspinatus and infraspinatus   →   loss of lateral shoulder support   →   sudden lateral outward motion of shoulder during weightbearing and   →   prominent scapular spine.
  • Often several other nerves in the brachial plexus appear to be involved.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Hahn C (2008)Common peripheral nerve disorders in the horse.In Pract30(6), 322-329 VetMedResource.
  • Dutton D Met al(1999)Nonsurgical treatment of suprascapular nerve injury in horses: 8 cases (1988-1998).JAVMA214(11), 1657-1659 PubMed.
  • Schneider R K and Bramlage L R (1990)Suprascapular nerve injury in horses.Comp Contin Edu Pract Vet12(12), 1783-1789 VetMedResource.
  • Duncan I D, Schneider R K and Hammang J P (1987)Subclinical entrapment neuropathy of the equine suprascapular nerve.Acta Neuropathol (Berl)74(1), 53-61 PubMed.
  • Schneider J Eet al(1985)Scapular notch resection for scapular nerve decompression in 12 horses.JAVMA187(10), 1019-1020 PubMed.


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