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


Swelling on Back of Lower Limb, Flexor Tendon Area


This observation refers to swelling of the back surface of a lower limb, above the fetlock but below the carpus of a front limb or hock of a hind limb.

The flexor tendons are CRITICAL weight bearing structures, and any swelling of this area could be a sign of injury to these structures. Be especially concerned if this observation is accompanied by lameness at the walk.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If lameness is noticeable at the walk.
    • If the area seems painful to the touch.
  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If there is modest or little lameness but significant swelling.
    • 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.
    • If the swelling is mild or moderate, and not increasing rapidly.

your role


What To Do

Assess your horse's general health using the Whole Horse Exam (WHE), paying particular attention to the presence or absence of fever, and lameness visible at the walk. Compare the look and feel of that limb to the others. Look carefully for any breaks in the skin or hair loss that could indicate trauma. Flex the lower joints and notice whether there is a pain response.

Always check the sole of the hoof, and assess for digital pulse and heat in the hoof. Gently press the whole swollen part with your fingers, looking for a pain response. Move the horse in left and right circles, at the walk, to assess degree of lameness. (It is best not to evaluate the horse at the trot. Depending upon the nature of the injury, this could worsen it.) When in doubt, always confine a horse with swelling of the lower limb until evaluated by a vet.

NEVER purchase a horse with a swelling here without a veterinary pre-purchase exam!

What Not To Do

Do not exercise a horse with injury to this area, even if it is mild, as this may worsen an injury.

NEVER purchase a horse with a swelling here without a veterinary pre-purchase exam!

your vet's role

In almost every case, swellings in this area should be evaluated by your vet. A meticulous exam and all necessary diagnostics are strongly encouraged. While these diagnostics may add significant expense to your vet bill, this is preferable given the nature of the injury, and the dire consequences of mismanaging or underestimating the complications associated with injuries to this area. Through their initial exam, your vet usually has a sense of whether the injury involved the critical weight bearing structures. Ultrasound and radiography may add valuable information.
Questions Your Vet Might Ask:
  • Do you know how this happened?
  • What does the horse do for a living?
  • Is the swelling over the back of the limb, or more on the side?
  • When did you first notice this problem?
  • What is the horse's exercise and performance history leading up to this?
  • When was the horse last ridden?
  • Is the horse limping or lame?
  • If the horse is lame, how lame?
  • Can you send me a photo?
  • What are the results of the Whole Horse Exam (WHE)?

Diagnoses Your Vet May Consider

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

Very Common
Less Common
more diagnoses

Author: Doug Thal DVM Dipl. ABVP