What you see. The starting point for addressing any equine health related issue is your observation.


Limb Folds or Collapses when Bearing Weight


A system of bones, tendons and ligaments within the horse's legs lock the limb into a resting weight bearing position. Normal horses can doze on their feet, exerting minimal muscular effort. This system of ropes and pulleys is known as the "passive stay apparatus" in the front limb and the "reciprocal apparatus" in the hind limb. Normal spinal and nerve function are also required for this system to function properly.

If any component of this system is damaged, then limb function is compromised and the horse might collapse when they bear weight. Loss of this function usually causes a horse great distress as they repeatedly try to bear weight, only to have the limb collapse under their weight.

I differentiate this from a non-weight bearing lameness. In this case, it is the lack of structural integrity that is causing the horse distress. Pain may be playing a role but it is less this than the loss of weight bearing ability. Examples of injuries that can cause this collapse to occur is radial nerve paralysis in the forelimb, sciatic paralysis or the severing of the gastrocnemius muscle in the hind limb.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours

your role


What To Do

When faced with this observation, contact your vet immediately. If non weight-bearing persists, there is danger to the other (supporting) limb. If possible, move the horse into an area with moderately deep, soft bedding where they can lie down. Be careful of the horse collapsing and injuring you.

your vet's role

Your vet will try to determine the cause of this dysfunction. Depending on the injury, splinting can sometimes be used to position the limb into bearing weight while healing takes place.
Questions Your Vet Might Ask:
  • Can I have your location and directions to get to you as soon as possible?
  • When did you first notice this?
  • What is the horse's age, sex, breed and history?
  • Does the horse have a history of accident or injury?
  • Do you notice evidence of physical injury, such as hair loss or swelling?
  • Was the horse recently anesthetized?
  • What are the results of the Whole Horse Exam (WHE)?

Treatments Your Vet May Recommend

A way to resolve the condition or diagnosis. Resolving the underlying cause or treating the signs of disease (symptomatic treatment)

Very Common
more treatments

Author: Doug Thal DVM Dipl. ABVP