The stifle locking mechanism (Figure 3.25) enables the horse to lock the stifle out completely, preventing any flexion during muscle relaxation on rest.The group of muscles that perform this action comprise the quadriceps femoris and tensor fasciae latae, which have insertions on the intermediate patellar ligament. One such adaptation is the development of a locking mechanism in its stifle that keeps the hindleg in extension and allows the horse to rest while standing, with virtually no muscular effort. The stifle joint (often simply stifle) is a complex joint in the hind limbs of quadruped mammals such as the sheep, horse or dog.It is the equivalent of the human knee and is often the largest synovial joint in the animal's body. With UFP the ligament is lax or longer and hangs up on the medial side of the femur which causes pain and a stiff leg which drags the toe behind. Frequently this leg "pops" as the limb comes forward. One especially clever adaptation is a locking mechanism in the stifle, which allows your horse to keep standing while sleeping – all with minimal muscular effort. The stifle joint has a locking mechanism which is designed to allow the horse to be able to sleep standing up. The stifle is not meant to lock up while the horse is walking or exercising. Locking stifles aren’t limited to one breed or type of horse or pony, but they are somewhat more common in horses that have very upright hindlimb conformation, with overly straight angles of the hock and stifle … Horses can stand for long periods of time without lying down because they can lock the stifle in one leg and relax the other leg so standing requires less muscular effort.

A locked stifle or ‘upward fixation of the patella’ occurs when the natural locking mechanism fails to unlock quickly and spontaneously. But this mechanism can also cause trouble. when my horse first showing signs of locking stifle my vet advised me to walk him up hills 30 min per day it built up his muscles really well and it worked. The horse’s quick reflex contractions prevent accidental locking of the patella but induce stride after … passive stay apparatus, hindlimb The passive stay apparatus in the horse's hindlimb allows the horse to stand using minimal muscular energy. 1. The apparatus uses a combination of two anatomical features: the first is the stifle locking mechanism which enables the stifle to be 'locked' (immobilised) by hooking the patella and the medial patellar ligament over the medial trochlear ridge of the femur. The problem isn't grounds for putting the horse down - while the emaciated body and worms and possible lice might end up doing him in, the stifle problem shouldn't. Sticky or Locking Stifle in a Horse - Cause and Treatment 'Sticky Stifle' is a result of a slight problem with the locking mechanism which fixes the stifle joint and allows the horse to stand sleeping - as a result, the rest of the horse's hind leg is affected.
The second element, the reciprocal mechanism (illustrated in DARK RED), ensures that the stifle and hock joints work in unison with one-another. The old treatment was to "clip" or "cut" the stifle. The first component involves the stifle-locking mechanism (illustrated in GREEN). Sticky or Locking Stifle in a Horse - Cause and Treatment 'Sticky Stifle' is a result of a slight problem with the locking mechanism which fixes the stifle joint and allows the horse to stand sleeping - as a result, the rest of the horse's hind leg is affected. The stay apparatus has three main components; patellar locking, the reciprocal mechanism and the check apparatus.

The suspensory apparatus locks the lower leg. This mechanism, when engaged, enables the horse to rest its caudal body weight on the "locked" stifle joint.

Looking after your horse’s stifle He would always get locked stifles during work we would trot for 10 min then start to walk and as soon as we went to trot again it happened. Locking Stifle Syndrome in the gaited Horse Part 1 A common physical affliction among gaited horses is upward fixation of the patella, otherwise known as locking stifles.The symptoms of this may be so subtle as to cause the horse owner many nights of restless, worried wondering, or so obvious that it seems an otherwise healthy horse has become functionally useless. Because of this mechanism, the stifle and the hock must move together, so when the stifle is locked, the hock can’t move, either.