The structure of the horse’s leg below the knee and hock
The horse has no muscle below the knee and hock, instead, the support structure and mechanism of locomotion consists of bone, tendon and ligaments.
There are a few bones below the knee and hock namely the cannon bone and the splint bones which connect to the fetlock joint, the long pastern bone, the short pastern bone and the pedal bone which is encased entirely in the hoof along with half of the short pastern. There are two small bones called the sesamoids which sit behind the fetlock joint and there is also a very small bone which is entitled the navicular bone which sits around the back of the joint between the pedal bone and the short pastern. Connecting these to the muscles higher up the leg is a selection of tendons and ligaments which act as stays and pulleys for static support and dynamic movement.
There are vital structures that run down the front of the horse’s leg but these are of far less interest to the horse owner than those that run down the back of the leg. This is because the connecting tendons and ligaments at the back of both the horse’s fore and hind limbs are much more vulnerable to injury due partly to their immense load bearing requirements and also potential interference from the hind legs certainly in the case of the forelimbs. These are the structures:-
- Superficial Digital Flexor Tendon – this originates from the muscles above the knee and hock runs down the back of the leg and attaches to both the long and short pastern bones
- Deep Digital Flexor Tendon – this originates from the muscles above the knee and hock and runs down the back of the leg passing behind the navicular bone before attaching to the wings of the pedal bone
- Suspensory Ligament – this originates at the top of the cannon bone and it runs down the splint bones to the fetlock where it splits into two with each branch attaching to the sesamoid bones at the back of the fetlock joint
- Check Ligament – this originates from the carpal bones at the back of the knee and supports the Deep Digital Flexor Tendon
This list is not exhaustive but these are the key structures that most horse owners are familiar with and the ones they worry about most when it comes to health and fitness and preventing injury.
It is very important to ensure that the horse’s legs are prepared properly for the work planned with the correct fittening regime which is designed not only for cardiovascular fitness but also preparing the horse’s limbs for the work they will have to do. Slow build up to fast work is essential to minimise the risk of injury to the tendons and ligaments and the correct leg protection forms part of this preparation and ongoing care. Despite all sensible precautions, horses do still injure themselves under saddle and when they are at liberty in the field. So, leg protection is not foolproof but it does help support the tendons and ligaments. It also protects against more superficial injuries caused by striking from another limb or knocking against a jump or obstacle.
Possible injuries and wounds which can occur to these vital structures
Tendon and ligament injuries can vary from slight sprains and strains to full-blown breakdown; the severity of the injury will dictate the treatment programme, the length of time the horse requires away from work and the likelihood of him returning to athletic function. Good horse management minimises the chances of such injuries occurring and protecting the vital structures of the limbs with appropriate boots or bandages is part of this but nonetheless, injuries can still occur.
On a simpler note, boots and bandages can also offer protection from the risk of more straightforward and superficial injuries such as knocks and blows, bang and minor cuts and abrasions.
Leg protection for competitive disciplines
Most riders will fit some sort of protection to their horse’s legs when they are being ridden. This leg protection will certainly extend to lungeing sessions where the horse has the potential to be quite fresh and excitable and leg boots may also in some circumstances be relevant to field turnout.
The type of leg protection chosen usually reflects the work the horse is doing and the environment. Most dressage horses will wear some form of polo or exercise bandage over padding or a breathable wrap when being worked in an arena on an artificial surface. Showjumping increases the potential for injury and the majority of riders will opt for leg protection, either in front or all around, this can include a selection from the following range:
- Brushing boots – a softer boot with a strike pad that sits on the inside of the horse’s leg between the knee and fetlock, secured by Velcro straps on the outside of the leg, worn both in front and behind according to rider preference
- Tendon boots – for the front legs only, these boots are a solid shell that encases the backs of the front limbs and are open to the front of the leg with straps running across the front of the leg and securing either with a clip or Velcro on the outside of the limb.
- Fetlock Boots – fitted to the hind limbs only, fetlock boots are used to protect against brushing and strike injuries and sit lower on the leg than a brushing boot. They are secured above the fetlock joint with a strike pad over the joint to shield it. Fetlock boots are usually made of a hard, moulded shell secured with a sole, broad strap.
- Overreach boots – made of either rubber or neoprene, these boots are fitted to the front feet to protect the bulbs of the heel from strike injuries from the hind feet. They should sit above the heel when the horse is in halt but as he moves. The boot sinks down momentarily to protect the heels from injury. Overreach boots are controversial and many event riders feel they can bring down a horse whilst it is galloping; they certainly can be a trip hazard.
- Speedycut Boots – these are a brushing boot with an extra area of protection sited at the top of the boot usually shaped in an arc and are worn only on the hind legs. They are designed for horses who have a high action behind when galloping and can strike into themselves above the usual range of protection of a standard brushing boot.
- Exercise bandages – a shorter elasticated bandage sitting just below the knee and above the fetlock, fitted over padding, a bandage has the dual benefit of offering both protection and support.
Leg protection is also dictated to some degree by the horse’s conformation. Horses that are close in front or behind will almost certainly brush and require leg protection most of the time. Some horses are also more prone than others to overreaching. This is why some owners choose to use leg protection when the horse is at liberty in the field.
Possible problems with boots and bandages
Any vet will tell you that a badly fitting bandage which can cause pressure points is worse than no bandage or protection at all. The main things to be concerned about are pressure points and uneven pressure which is why bandages should only be fitted by an experienced person. It is also usual to have the same person put on all the bandages the horse is wearing be that two or four as they are more likely to apply the same pressure. Most bandages these days have sticky straps to secure them but if the bandage has ties, then the bow should be tied on the outside of the leg and never at the back over the tendons and ligaments.
Like other aspects of horse equipment, some boot designs will suit certain horses and not others. Leg boots are sold in pairs so it is possible to have one size in front and a different one behind, most boots are sold in pony, cob and horse or full size. Riders often have everyday work boots and keep a set for best, just for competition or clinics. It is important the horse is comfortable in the boots and it is not a wise practice to use new or untried boots for the first time at a competition.
One of the great equine debates centres on turning horses out in the field in protective boots because there is a school of thought which maintains that prolonged covering of this part of the horse’s leg will heat up the tendons and ligaments. Think about the time the horse may spend competing and wearing leg protection which is a fraction of the time compared to a long day out in the field. Boots worn for long periods can rub and they will significantly increase the temperature of the sensitive structures. Overheating tendons and making them pliable and more elastic is thought by some to increase their susceptibility to injury although others dispute this. Whatever the correct position, manufacturers have responded to these concerns by developing boots which have vents for air cooling.
Protection whilst travelling
The two main options when travelling a horse are either travel bandages or travel boots. A travel boot is a stiff yet flexible shaped leg wrap which secures with broad Velcro straps and protects from the knee on the front leg and the hock on the hind right down to the bulbs of the heel. Travel boots are easy and quick to put on.
The alternative is travel bandages which is a non-elasticated fleece bandage applied over padding such as fibregee or gamgee. They extend from below the knee and hock down to the pastern and are very similar to stable bandages, usually not quite so long, to allow overreach boots to be fitted for travel if desired.
Travel boots are the norm these days because they are so convenient but they offer less support than travel bandages and if they slip down the leg, can prove a hazard if the horse treads on them and becomes caught up. For long distance journeys, horses usually travel without any leg protection at all because they can overheat and of course, rescue centres will often travel horses unprotected and even loose because these animals may never have been handled or not handled sufficiently to tie up and accept travel equipment.
Protective leg wear should be carefully chosen based on the horse, the environment he is to work in and the discipline or competitive event. Care should always be taken to ensure that boots and bandages fit correctly and are clean and free of dirt, grime and sweat which can act as a local irritant. Boots and protective equipment should be cleaned and washed thoroughly just in the same way that tack is cared for.
In general, protecting the horse’s lower leg is a good thing but it is only part of the picture; correct management, working on appropriate surfaces, preparing the horse with a proper fitness programme is equally if not more important than the choice of leg wear on a particular day.
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