Guide to the Tendon Sheath in Horses

Posted on February 27, 2023 by Categories: Cryochaps, Exoskeleton
tendon and fetlock boots

The tendon sheath is a vital structure that helps to protect the horse’s tendons. This blog article outlines the role of the tendon sheath, as well as issues that can affect the tendon sheath including injuries and infections. Finally, it outlines how our ice wraps and exercise boots can help during exercise, after exercise and in the event of an injury. 

What is the Tendon Sheath in Horses?

The horse’s lower legs do not contain any muscles. Instead, the bones are moved by long tendons, which are attached to the parent muscles in the upper legs. Some of these tendons must run over joints, such as the hock, knee (carpus) and fetlock. Due to the amount of movement that occurs as the horse changes speed or direction, the tendons require some additional protection in the joint areas. 

The tendon sheaths are fluid-lined tubes that encase and protect the tendons as they pass over the joints. The synovial fluid acts as a lubricant, allowing the tendon to glide over the joint as the horse moves. 

The main tendon sheaths are:

  • The extensor sheath and the lateral digital flexor sheath, in the hock
  • The carpal sheath, in the knee
  • The digital sheath, in the fetlock

Tendon Sheath Injuries

Like the tendons themselves, the tendon sheaths can be vulnerable to injury. When a tendon sheath is injured or infected, it fills with synovial fluid and may look enlarged or swollen. The horse may exhibit lameness, heat or swelling in the affected area. 

Tenosynovitis is when the tendon sheath becomes inflamed. This condition may be primary (i.e. due to an injury to the tendon sheath itself) or secondary (i.e. due to an injury to the tendon within the tendon sheath). Tenosynovitis can also be infectious (usually caused by a wound) or non-infectious (usually involving an impact). 

An infected tendon sheath can be very serious. Therefore, it is important to always contact your vet immediately if you notice a wound in the area covering or close to a tendon, tendon sheath or joint. 

Windgalls, Windpuffs and Thoroughpins

Windgalls and windpuffs are usually harmless, but can indicate previous irritation or inflammation of the digital tendon sheath at some point. They occur when the tendon sheath lining has been stretched due to it being filled with synovial fluid at some point.

Thoroughpins are similar to windgalls, except they tend to occur in the lateral digital flexor sheath. 

Protect Your Horse’s Legs with Exoskeleton Tendon and Fetlock Boots

Your horse’s legs, especially the soft tissues, can be vulnerable to injury during exercise. Our fetlock and tendon boots provide excellent protection against strikes and overreach injuries. They are also FEI legal for Young Horse showjumping classes, making them suitable for most affiliated showjumping and eventing competitions. Super lightweight and easy to apply, the Exoskeleton tendon and fetlock boots are quick and easy to use, clean and dry.

Furthermore, our tendon boots use forced convection cooling technology to force air across the back of the horse’s legs as it moves, minimising the amount of heat that is allowed to build up in the leg during exercise. 

The Exoskeleton tendon and fetlock boots are available in black and tan, so you can purchase a matching set of exercise boots for your horse. 

Cryochaps Equine Ice Wraps for First Aid & Recovery

It’s useful to have ice at the ready in the event of a tendon sheath injury or other soft tissue injury. The Cryochaps Absolute Wrap is a handy, versatile equine ice wrap. Whether your horse requires ice and compression whilst you wait for the vet; during rehabilitation or as part of your regular cool-down routine, the Absolute Wrap provides a versatile solution.

Designed to be quick and easy to apply, the Absolute Wrap is suitable for pasterns, fetlocks, knees and hocks. The Absolute Wrap is sold as a pair.