Skip to main content
menu sluit menu
Home Home
Login
Main navigation
  • Library
  • Calendar
  • e-Learning
  • News
    • Veterinary News In this section you find veterinary news
    • Recent Additions All content that was recently added to the IVIS library
  • Get involved
    • Donate Support IVIS, make a donation today
    • Media kit Promote your e-learning & events on IVIS
    • Add your e-learning & events to the IVIS calendar
    • Publish on IVIS Publish your work with us
  • About
    • Mission Our Mission Statement
    • What we do More info about IVIS and what we do
    • Who we are More info about the IVIS team
    • Authors See list of all IVIS authors and editors
  • Contact
User tools menu
User tools menu
Main navigation
  • Library
  • Calendar
  • e-Learning
  • News
    • Veterinary News In this section you find veterinary news
    • Recent Additions All content that was recently added to the IVIS library
  • Get involved
    • Donate Support IVIS, make a donation today
    • Media kit Promote your e-learning & events on IVIS
    • Add your e-learning & events to the IVIS calendar
    • Publish on IVIS Publish your work with us
  • About
    • Mission Our Mission Statement
    • What we do More info about IVIS and what we do
    • Who we are More info about the IVIS team
    • Authors See list of all IVIS authors and editors
  • Contact
Follow IVIS
  • Twitter
  • Facebook
Support IVIS

Breadcrumb

  1. Home
  2. Library
  3. American Association of Equine Practitioners
  4. AAEP Resort Symposium - Costa Rica, 2010
  5. The Art and Science of Equine Neurology - Peripheral Nerves & Stringhalt
AAEP Resort Costa Rica 2010
Back to Table of Contents
Add to My Library
Close
Would you like to add this to your library?

Get access to all handy features included in the IVIS website

  • Get unlimited access to books, proceedings and journals.
  • Get access to a global catalogue of meetings, on-site and online courses, webinars and educational videos.
  • Bookmark your favorite articles in My Library for future reading.
  • Save future meetings and courses in My Calendar and My e-Learning.
  • Ask authors questions and read what others have to say.
Sign in Register
Comments
Share:
  • Facebook
  • LinkedIn
  • Mail
  • Twitter

The Art and Science of Equine Neurology - Peripheral Nerves & Stringhalt

Author(s):

R.J. MacKay

In: AAEP Resort Symposium - Costa Rica, 2010 by American Association of Equine Practitioners
Updated:
JAN 26, 2010
Languages:
  • EN
Back to Table of Contents
Add to My Library
Close
Would you like to add this to your library?

Get access to all handy features included in the IVIS website

  • Get unlimited access to books, proceedings and journals.
  • Get access to a global catalogue of meetings, on-site and online courses, webinars and educational videos.
  • Bookmark your favorite articles in My Library for future reading.
  • Save future meetings and courses in My Calendar and My e-Learning.
  • Ask authors questions and read what others have to say.
Sign in Register
SHARE:
  • Facebook
  • LinkedIn
  • Mail
  • Twitter
    Read

    Peripheral Nerve Injury  

    Mechanical injuries to peripheral nerves occur because of compression, entrapment, transection,  laceration, ischemia, crushing, stretching, or chemical or burn damage.1,2 Neurapractic lesions are characterized by a failure of conduction of the action potential across the injured axonal  segment.3 Axonotmesis is axonal interruption, while neurotmesis reflects disruption of endoneurium, perineurium, and/or epineurium. Recovery by axonal regrowth is unlikely after  neurotmesis.4 After axonotmesis of motor nerves, muscle reinnervation occurs by 2 separate  mechanisms: collateral sprouting and axonal regrowth.1 If there is incomplete loss of axons, reinnervation of muscle units by sprouting occurs in days to weeks. Reinnervation by axonal  regrowth occurs at a rate of 1 mm per day (approximately 1 inch/month). Reinnervation may not be possible after more than 12 months although this remains a controversial issue. Peripheral nerve injuries are characterized by weakness of the innervated muscle accompanied within 2-4  weeks by appreciable atrophy. When the injured nerve supplies important extensor muscles of  the limbs (e.g., radial, femoral, sciatic, peroneal), there is obvious alteration of gait. Areas of  cutaneous anesthesia occasionally accompany peripheral nerve injuries. Over the neck and trunk, cutaneous sensory innervation occurs in defined bands associated with segmental dermatomes. Damage to a peripheral spinal nerve or dorsal nerve root results in cutaneous  anesthesia/hypalgesia over the supplied dermatome. With damage to the pudendal nerve or its  sacral nerve roots, there is anesthesia/hypalgesia of the perineal area. In contrast, relatively small  autonomous zones have been defined for sensory components of the ulnar, musculocutaneous, median, femoral, tibial and peroneal nerves.5,6 Sympathetic fibers are distributed with peripheral  nerves, so denervated skin also may be evident as circumscribed spontaneous sweating. The  most common and important syndromes of mechanical injury to peripheral nerves of the limbs are described below.6-8 

    Suprascapular Nerve  

    Arises from C6 and C7. Injury occurs most commonly when a horse’s shoulder is impacted at speed such that the nerve is injured as it curls around the front of the neck of the scapula. There  immediately is laxity and lateral instability of the shoulder joint, which bows out or “pops” as the  affected limb bears weight. Within 2-4 weeks of injury, there is obvious atrophy of the supraspinatus and infraspinatus muscles (sweeney). Successful reinnervation is evident as recovery of muscle bulk in the ventral part of the supraspinatus muscle beginning within 3  months of injury. Maximal recovery takes an additional 3-12 months. Regrowth of the  suprascapular nerve can be facilitated by surgery to resect scar tissue (external neurolysis) and  reduce tension on the nerve as it crosses the front of the scapula (often performed 3-6 months  after injury)

    Radial Nerve  

    The radial nerve innervates a flexor of the shoulder and the extensors of the elbow, carpal, and  digital joints. It arises from T1. The nerve root may be lacerated by fractures of the C7 or T1  vertebrae or first rib. The nerve is commonly damaged as a result of humeral fracture9 and can be  injured at the brachial plexus by trauma to the shoulder region. Ischemic damage may occur in horses anesthetized in lateral recumbencyT.10 The lower part of the nerve may be damaged by  dislocation or fractures that involve the elbow.  

    Horses with complete radial paralysis stand with the shoulder extended, the elbow “dropped” and  the dorsum of the hoof rest on the ground. When forced to walk, the horse may partially protract the limb by exaggerated extension of the shoulder; however, the toe drags and the horse  collapses on the limb during the weight-bearing phase of the stride. If the site of damage is distal, the shoulder and elbow are normal. Although the radial nerve has numerous cutaneous sensory  branches, injury to this nerve does not result in any consistent area of cutaneous anesthesia. 

    Musculocutaneous Nerve  

    Arises from C7 and C8 and supplies flexors of the elbow. Injury is uncommon and causes only  transient toe-dragging. The shoulder may be held in a flexed position and the elbow in an extended position. There is hypalgesia/anesthesia over the dorsomedial aspect of the knee and  proximal metacarpus and atrophy of the biceps and brachialis muscles  

    Median and Ulnar Nerves  

    The median nerve arises from C8 and T1 and the ulnar nerve from T1 and T2. Injury to either can be caused by injury at the brachial plexus or along the medial aspect of the upper limb. There is a “tin soldier” gait, with decreased flexion and dragging of the toe and hypalgesia/analgesia of the skin of the caudal forearm, lateral metacarpus, and medial pastern areas and atrophy of the carpal and digital flexors.  

    Femoral Nerve  

    Arises from L3 to L5. The femoral nerve innervates muscles that flex the hip and extend the  stifle. The nerve can be damaged by ilial, femoral or vertebral fractures. Ischemic injury caused by prolonged stretch or increased tissue pressure during anesthesia in dorsal recumbency or after severe prolonged dystocia.11 With unilateral paralysis the pelvic limb is abnormally flexed usually with the foot flat on the ground and buckles when the limb bears weight. In the case of  bilateral involvement, the horse is either unable to rise or stands uncomfortably in a crouched  position. If the nerve injury occurs proximal to the saphenous branch, there is anesthesia/hypalgesia of the skin over the medial surface of the thigh and atrophy of the  quadriceps muscle. 

    [...]

    View full text
    Back to Table of Contents
    Add to My Library
    Close
    Would you like to add this to your library?

    Get access to all handy features included in the IVIS website

    • Get unlimited access to books, proceedings and journals.
    • Get access to a global catalogue of meetings, on-site and online courses, webinars and educational videos.
    • Bookmark your favorite articles in My Library for future reading.
    • Save future meetings and courses in My Calendar and My e-Learning.
    • Ask authors questions and read what others have to say.
    Sign in Register
    References

    1. Sellon DC, Monroe VL, Roberts MC, et al. Pharmacokinetics and adverse effects of butorphanol administered by single intravenous injection or continuous intravenous infusion in horses. Am J Vet Res 2001;62:183-189. - PubMed -

    ...
    Show all
    Comments (0)

    Ask the author

    0 comments
    Submit
    Close
    Would to like to further discuss this item?

    Get access to all handy features included in the IVIS website

    • Get unlimited access to books, proceedings and journals.
    • Get access to a global catalogue of meetings, on-site and online courses, webinars and educational videos.
    • Bookmark your favorite articles in My Library for future reading.
    • Save future meetings and courses in My Calendar and My e-Learning.
    • Ask authors questions and read what others have to say.
    Sign in Register
    About

    Copyright Statement

    © All text and images in this publication are copyright protected and cannot be reproduced or copied in any way.
    Related Content

    Readers also viewed these publications

    • Journal Issue

      Veterinary Evidence - Vol 8 N°1, Jan-Mar 2023

      In: Veterinary Evidence
      JAN 28, 2023
    • Proceeding

      SFT - Theriogenology Annual Conference - Bellevue, 2022

      By: Society for Theriogenology
      JAN 10, 2023
    • Proceeding

      ACVIM & ECEIM - Consensus Statements

      By: American College of Veterinary Internal Medicine
      NOV 11, 2022
    • Journal Issue

      Veterinary Evidence - Vol 7 N°2, Apr-Jun 2022

      In: Veterinary Evidence
      OCT 07, 2022
    • Journal Issue

      Veterinary Evidence - Vol 7 N°3, Jul-Sep 2022

      In: Veterinary Evidence
      OCT 04, 2022
    • Journal Issue

      Veterinary Practice Management Articles - Veterinary Focus

      In: Veterinary Focus
      AUG 05, 2022
    • Chapter

      Thoracolumbar and Sacral Spine

      In: Current Techniques in Small Animal Surgery (5th Edition)
      AUG 04, 2022
    • Chapter

      Nutrition

      In: The Clinical Companion of the Donkey (2nd Edition)
      JUL 09, 2022
    • Chapter

      Pharmacology and Therapeutics

      In: The Clinical Companion of the Donkey (2nd Edition)
      JUL 03, 2022
    • Chapter

      Sedation, Anaesthesia and Analgesia

      In: The Clinical Companion of the Donkey (2nd Edition)
      JUN 05, 2022
    • Chapter

      The Geriatric Donkey

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 20, 2022
    • Chapter

      Euthanasia and the Post-Mortem Examination

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 20, 2022
    • Chapter

      Appendix 7: Example Diets: for the mature, pregnant and lactating donkey

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 12, 2022
    • Chapter

      Appendix 2: Donkey Weight Estimator

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 12, 2022
    • Chapter

      Appendix 1: The Clinical Examination

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 12, 2022
    • Chapter

      Appendix 5: Monitoring your Donkey’s Quality of Life

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 12, 2022
    • Chapter

      Appendix 6: Professional record of Assessment for Quality of Life

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 12, 2022
    • Chapter

      Appendix 3: Body Condition Scoring

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 12, 2022
    • Chapter

      Appendix 4: Parameters: Biochemistry and Haematology

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 12, 2022
    • Chapter

      The Care of the Foal

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 12, 2022
    • Chapter

      Approach to the Dull Donkey

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAY 07, 2022
    • Chapter

      Parasitology

      In: The Clinical Companion of the Donkey (2nd Edition)
      APR 26, 2022
    • Chapter

      The Foot

      In: The Clinical Companion of the Donkey (2nd Edition)
      APR 06, 2022
    • Chapter

      Infectious Diseases

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAR 28, 2022
    • Chapter

      The Musculoskeletal System

      In: The Clinical Companion of the Donkey (2nd Edition)
      MAR 24, 2022
    • Load more
    Provided by:
    AAEP - American Association of Equine Practitioners

    The AAEP represents nearly 9,300 veterinarians and veterinary students in 61 countries who cover a broad range of equine disciplines, breeds and associations. The AAEP is primary resource for education, professional development and ethical standards for its members. The AAEP and its members are recognized as the voice and authority for the health and welfare of the horse. The AAEP conducts regular strategic planning every three to four years in order to establish priorities and set direction for the association over the current planning horizon.  The AAEP is a respected source of information for influencing public policy.  

    Learn more
    Back To Top
    Become a member of IVIS and get access to all our resources
    Create an account
    Sign in
    Leading the way in providing veterinary information
    About IVIS
    • Mission
    • What we do
    • Who we are
    Need help?
    • Contact
    Follow IVIS
    • Twitter
    • Facebook
    International Veterinary Information Service (IVIS) is a not-for-profit organization established to provide information to veterinarians, veterinary students, technicians and animal health professionals worldwide using Internet technology.
    Support IVIS
    © 2023 International Veterinary Information Service
    • Disclaimer
    • Privacy Policy