Canis ISSN: 2398-2942

Suprascapular neuropathy

Contributor(s): Kyle Braund

Introduction

  • Uncommon.
  • Single nerve lesion.
  • Cause: probable trauma to the suprascapular nerve.
  • Signs: chronic lameness in a forelimb (rarely bilateral) with pronounced atrophy of supraspinatus and infraspinatus muscles.
  • Diagnosis: history, clinical signs.
  • Treatmentsurgical, eg tenotomy of the infraspinatus tendon.
  • Prognosis: good.

Pathogenesis

Etiology

  • Trauma?

Predisposing factors

General
  • Most commonly in dogs with infraspinatus contracture, lameness is observed after a period of vigorous exercise rather than after direct trauma to the shoulder.

Pathophysiology

  • The pathogenesis of this condition is unclear.
  • Muscle contracture (shortening of muscle not caused by active contraction) may result from trauma to muscle fibers, nerves (see Pathophysiology) or blood vessels (ischemic contracture).
  • Injury, eg by a direct blow to the nerve or by over-stretching the nerve as a result of the shoulder being thrust caudally in a violent fashion, to the suprascapular nerve as it passes around the cranial edge of the scapula can result in nerve fiber degeneration and subsequent nervogenic atrophy in the muscles. This nerve supplies infraspinatus and supraspinatus muscles.

Timecourse

  • Usually 2-4 weeks (or longer) for muscle atrophy to develop.

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.
  • Dillon E A, Anderson L J, Jones B R (1989) Infraspinatus muscle contracture in a working dog. New Z Vet J 37 (1), 32-34 PubMed.
  • Carberry C A & Gilmore D R (1986) Infraspinatus muscle contracture associated with trauma in a dog. JAVMA 188 (5), 533-534 PubMed.
  • Bennett R A (1985) Contracture of the infraspinatus muscle in dogs: a review of 12 cases. JAAHA 22 (4), 481-487 VetMedResource.
  • Pettit G D & Slatter D H (1972) Infraspinatus contracture associated with suprascapular paralysis in a dog. JSAP 13 (12), 699-702 PubMed.


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