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


Swollen Hock, Generally


The hock is an anatomically complicated area. There are 4 joints, tendon sheaths and a variety of other structures here, one of which or more can sustain injury or disease. Large fluid swellings are usually associated with the top joint or tendon sheaths.

A clearly defined bubble that is visible on the front, side, and inside of the hock (bog spavin) indicates excessive fluid in the top, high motion joint of the hock. It can be caused by injury to that joint including fractures, osteochondrosis, or joint infection. It also commonly appears mysteriously, with no known cause, called by the old horsemen's term Bog or Bog Spavin. Often this type of swelling is not associated with lameness.

A diffusely swollen "big" hock is usually caused by traumatic injury or infection. The joint can also mysteriously fill with blood (Blood Spavin).

A hard knot of swelling on the lower inside of the hock (Bone spavin) usually relates to arthritis of the lowest joint of the hock.

The swellings described above differ from "curb", a swelling below the point of the hock, a "capped hock" a swelling at the point of the hock, and "thoroughpin" a swelling of the flexor tendon sheath in the hock.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If the horse cannot bear weight on the limb or seems otherwise distressed.
    • If the results of the Whole Horse Exam (WHE) in the resting horse indicate fever (Temp >101F/38.3C) or heart rate greater than 48 BPM.
  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If the horse can bear weight on the limb but has a pronounced limp.
    • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.
  • Code Yellow

    Contact Your Vet at Your Convenience for an Appointment
    • Even if the horse does not appear to be lame to you.
    • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.
You also might be observing
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your role


What To Do

If you notice that your horse has a swollen hock, assess their general health using the Whole Horse Exam (WHE), paying particular attention to the specific location of the swelling, the existence of and degree of lameness, and the rectal temperature.

Feel the affected area carefully for heat and pain to pressure. Look for wounds and areas of hair loss. Consider the softness or hardness of the swelling. Lift the limb to get a sense of whether flexion hurts. Determine whether your horse is lame at the walk or trot. Contact your vet with your findings and concerns. You may also take a photo of the swelling and share it with your vet, as it may provide valuable information about the significance and urgency of the situation.

your vet's role

Your vet assess the nature of the swelling, and the particular structures involved, and determines a course of action. In many cases, further diagnostics are not necessary. The most important factor is always the presence or absence of lameness, and whether it relates to the hock swelling.
Questions Your Vet Might Ask:
  • How is your horse's attitude and appetite?
  • Have you noticed the horse showing lameness?
  • When did you first notice the swelling?
  • How does this area compare to the same area on the other hock?
  • What is the horse's age, sex, breed and history?
  • How severe do you think the lameness is?
  • Is the problem present on both sides?
  • Was the horse involved in an accident that you know of?
  • What are the results of the Whole Horse Exam (WHE)?
  • Can you send me a photo?

Diagnostics Your Vet May Perform

Figuring out the cause of the problem. These are tests or procedures used by your vet to determine what’s wrong.

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Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

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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)

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further reading & resources

Author: Doug Thal DVM Dipl. ABVP