Equis ISSN 2398-2977

Femoral nerve: trauma

Contributor(s): Frank Andrews, Caroline Hahn, Katrin Schmallenbach

Introduction

  • Cause: external trauma to the limb.
  • Signs:
    • Cannot support weight.
    • Lack of joint extension.
    • Decreased stride length.
    • Buckling of limb on weightbearing.
    • Flexion of stifle with automatic flexion of fetlock and hock.
    • Atrophy of quadriceps muscle.
    • Absence of patella reflex.
    • Loss of sensation to medial leg (mid-thigh to hock).
    • Bilateral injury.
  • Diagnosis: pelvic limb lameness.
  • Treatment: DMSO, corticosteroids, surgery.
  • Prognosis: good to fair.

Pathogenesis

Etiology

  • Damage to the femoral nerve can occur from an external blow to the limb or postanesthetic recumbency.
  • Bilateral femoral nerve injury has been reported in horses after general anesthesia and from sacroiliac luxation after dystocia in mares.

Pathophysiology

  • The quadriceps femoris group of muscles is innervated by the femoral nerve.
  • Inability to extend the stifle results from its paralysis.
  • As a consequence of stifle flexion, the tarsus and digit are flexed and the horse is unbale to bear weight on the limb.
  • The hock can still be flexed to pull the limb forward, but the patellar reflex is depressed or absent.
  • Hypalgesia of the medial thigh.

Timecourse

  • Atrophy of the quadriceps muscles (biceps femoris, vastus lateralis) may be seen within 1 to 2 weeks of the injury.

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.
  • Dyson S, Taylor P & Whitwell K (1988)Femoral nerve paralysis after general anesthesia.Equine Vet20(5), 376-380 PubMed.


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