Bovis ISSN 2398-2993

Radial limb paralysis

Contributor(s): Nick Bell, Sophie Mahendran , Roger Blowey

Introduction

  • Cause: direct trauma, humeral fractures, restraint in roll-over crushes.
  • Signs: non-weight bearing on the affected leg, with a dropped elbow.
  • Diagnosis: thoracic limb lameness with impaired cutaneous sensation.
  • Treatment: rest in a loose housed straw yard, NSAIDs.
  • Prognosis: good to grave depending on severity, clinical signs and response to NSAIDs.

Pathogenesis

Etiology

  • Direct trauma to the upper limb
    • Can occur in poor handling facilities, from running into objects or from trapping the limb in feeders.
    • Occasional injury during foot trimming from either a cow charging into a yoke on entry to a crush or from resting heavily on the yoke for prolonged periods.
    • A related but different injury can occur to the brachial plexus injury as a belly band cuts into the axilla.
  • Restraint for foot trimming or surgery in a roll-over crush.
    • Myopathy-compartmentalization syndrome.
  • Post-recumbency anesthesia.
    • Especially if the limb is malpositioned and stretched.
  • Fracture of the humerus.
  • Prolonged lateral recumbency on a hard surface from miscellaneous causes.

Pathophysiology

  • The radial nerve originates from the largest outflow from the brachial plexus, from spinal cord C7, C8, T1.
    • Innervates extensors of elbow, carpus and digit.
    • Sensory component to front of antebrachium.
  • The radial nerve passes across the lateral aspect of the distal humerus, proximal to the elbow joint.
    • Susceptible to trauma.
    • Also possible to damage the nerve by compression of the radial nerve roots between the scapula and the ribs, eg in a recumbent cow.
  • Not commonly damaged alone.

Timecourse

  • Some animals will recover within a few hours, particularly with prompt administration of Non-Steroidal Anti-inflammatory Drugs, (NSAIDs) Anti-inflammatory drugs: overview.
  • Prolonged paresis is possible with atrophy of triceps brachialis, extensor carpi radialis, ulnaris lateralis and the digital extensor muscles. However, these animals do not cope with the typical environment within the milking herd and so this is rarely seen in dairy herds.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Hartnack A K (2017) Spinal cord and peripheral nerve abnormalities of the ruminant. Veterinary clinics of North America: food animal practice 33 (1), 101–10 PubMed.
  • Constable P (2004) Clinical examination of the ruminant nervous system. Veterinary clinics of North America: food animal practice 20 (2), 185–214 PubMed.
  • Divers T J (2004) Acquired pinal cord and peripheral nerve disease. Veterinary clinics of north america: food animal practice 20 (2), 231–42 PubMed.

Other sources of information

  • Lahunta A & Divers T (2008) Chapter 12 - Neurologic diseases. In: Rebhun’s diseases of dairy cattle. 2nd edn. Saint Louis: W.B. Saunders. pp 504 - 60.
  • Blowey R W & Weaver A D. A color atlas of diseases and disorders of cattle. Elsevier.


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