Now, getting a photo of the hind legs that allows you a true angle and measurements is easier said then done. Most horses want to face toward their handler - and the camera man - which turns the hip away from the camera. This can slightly skew the angles necessary for true measurements.
The other problem I see most often, are horses who try to step under themselves, or leave a leg behind themselves when the picture is taken. When the hind leg is not directly under the horse, you have too many angles in motion to get a true idea of the horse's conformation.
The parts of the hind leg
- Orange dot - point of pelvis (the pelvic wing)
- Red dot - Point of hip (bony point at the buttocks)
- Yellow dot - stifle (same as a knee on a human)
- Blue dot - hock (same as ankle on human)
- Green dot - pastern (same as ball of foot on human)
- Pink dot - coffin joint (toes on a human)
Now, a lot of people get confused because an anatomy lover will use the "exact" terms to refer to the joints of a horse's hind leg, while a layman will use the term closest to what makes sense for them. Because of this, a horse's "knee" is most commonly it's hock on the hind leg, when in reality, the knee is up near the body, and called the stifle. The stifle even has a "knee cap" called the patella. The horse's thigh is located between the red and yellow dots, while its gaskin is between the yellow and blue dots. Both the gaskin and the thigh refer to muscle groups used to move the lower joints.
The ideal hind leg
Many flaws of the hind leg are horses who do not meet this angle. When judging conformation, you must be careful to take into consideration age (growth spurts will cause the hip to be high, and throw the entire pelvis and hind leg out from the vertical) and movement.
This does not mean his hind legs are flawed, but rather that as he shifts his weight forward, the supporting hind leg will trail behind until the weight transfers to the left hind. While this picture is "close" to being able to be used for a conformational analysis, the hind legs should not be judged from a stance like this.
Because of this, the angle of view for the hind leg will set the cannon bone well ahead of the vertical. His hock almost touches the line, but his cannon and pastern are well in front of it.
Also notice the direction this stallion's feet are pointing. Pretty much all of his toes are pointing in different directions, meaning that this pretty boy is not standing "true", and so most conformation lines taken from this type of wonky image won't be accurate.
I have to mention here, that I'm really glad right now that I did not delete these "wonky" pictures of the boys.
Now, there are many conformational faults of the hind legs, but today I will only deal with those seen from the side. Some you may have heard of, others are much less common terms.
Sickle Hocked and Out Behind - or excessively long hind limbs
I believe that this is the most common conformation "fault" seen in the hind legs. I use quotes around fault, because for some purposes, a sickle hocked horse can be just as useful in moderation, if not more useful then a proper hind leg. A horse with a sickle hock has too much angle in the hind legs. This allows the horse to have more action, but at the cost of more wear and tear on the legs. Sickle hocks are commonly seen in gaited horses and jumping horses, and recently have begun making an appearance in dressage horses. Of course, severe sickle hocks cause more severe strain, so disciplines using horses with sickle hocks are seen using very minor cases.
Now, to be fair, Sweetie is in a very awkward stage of growth in this image. Her hip is high, which alters the angle of her pelvis and all the joints of the hind leg below that. This makes her sickle hocked appearance more noticeable (hence why I used this picture as an example).
But when a horse has sickle hocks, it's often hard to get that horse to bear its weight with its hock lined up with the point of hip. Most commonly you will see the horses standing with their legs out behind them.
Basically, her hind leg is too long for her proper center of balance, so depending upon where she puts her balance (under her, or behind her) the "fault" will vary between sickle hocked and out behind.
Now, there is some debate about these 2 flaws. Dr. Deb Bennett has studied the measurements of many horses, and found that these flaws are the same, but through out history they were seen as 2 distinctly different problems.
This is because the leg is made up of more then just the hock. Horses with excessively long hind legs, whose hooves tend to have less heel will naturally stand under themselves, and bear weight on their heel. Horses who have a longer heel will naturally find it easier to camp their overly long hind legs out behind them, and bear weight closer to the toe of the hoof. Because of this, a sickle hocked mare can produce a camped out foal. I choose to refer to both problems as 'sickle hocked' to avoid confusion with the preferred show stance of several breeds (including Tennessee Walking Horses, Arabians, and Saddlebreds) who pose their horses in a stretched pose, and call it "camping them out".
Post Legged - or excessively short hind limbs
The next flaw of the hind legs is actually the opposite of sickle hocked. These horses have an overall shorter hind leg, and to balance their weight they tend to stand with little to no angles in the hind leg.
This results in the hock joint being open almost straight up and down. The line of her gaskin is much more vertical then the filly above, and her hind pasterns also tend to be straighter. This conformational fault will place strain on the stifle, and ligaments around the patella as they strain to compensate for the lack of flexion lower down.
Now, as with all things, post legged horses are preferred in some disciplines. For a while, the trend was for halter horses to be rather post legged, and sadly, I can not tell you why, as I know so very little about western halter classes. Now, in cutting and reining, post legged horses are often seen, and in some cases perform well. This is because when these horses get low in the front, they are naturally correcting the flaw of being too short in the hind legs, and reducing the strain by creating more angulation.
The conformation of the hind legs of a horse directly effects the job that a horse is suited for. Ironically, we most often look at the forehand of a horse before the hind legs though. While most conformational texts break up the faults of the hind leg more, in reality it all boils down to 2 things: are the legs too long or too short, and does the horse try to balance too far under or too far out behind.
The proportions of the hind leg can be properly calculated for each horse based upon using the vertical line, rather then needing to measure out percentages of overall body length. If the back of the cannon bone lies even with a vertical line falling from the point of the buttocks, then the horse's hind leg is of proper length and the angulation of the joints should be within the margin of error for the ideal.
The Sugarbush Draft Horse
Because of the mass of these horses (as draft horses) too short limbs in the hind can cause excessive strain, because the overall conformation of the Sugarbush Draft Horse is not beneficial to a horse that can bend low on the forehand.