In order for horses to travel properly and correct they must be sound in their feet and legs. Structural correctness refers to the horse's bone structure in all four legs. When evaluating a horse's legs you should view them from the front, side and hind perspectives. As viewed from the front, a horse's legs should be straight having equal amounts of forearm, knee, cannon bone, fetlock, pastern and hoof on either side of an imaginary vertical line that bisects the front leg. Deviations in the horse's structure from the front view include: toed-out, toed-in or pigeon-toed, offset with the knees to the inside or outside, base wide and base narrow.

Ideal Front View

Toed Out	Toed In	Base Wide	Base Narrow
Offset with Knees to Inside		Offset with Knees to Outside

The same is true when viewing horses from the rear. A horse's leg should be straight having equal amounts of gaskin, hock, cannon bone, fetlock, pastern and hoof on either side of an imaginary line that bisects the hind leg. Deviations in a horse's structure from the rear view include: cow-hocked or in at the hocks, base wide and base narrow.

Ideal Rear View	Cow Hocked	Base Wide	Base Narrow

When viewing horses from the side view it is also desirable for the horse to be straight in the front quarters and the hind quarters. Deviations in a horse's structure from the side view may include the following: buck-kneed or over in the knees, calf-kneed or back in the knees, sickle hocked or camped under, camped out behind and post legged or being too straight in the hind leg.

Ideal Side View	Buck Kneed	Calf Kneed	Camped Out
Sickle Hocked	Post Legged

In addition to the various unsoundness deviations, horses can also have a variety of Blemishes which should be identified and be considered faults during selection. Commonly observed blemishes and abnormalities are listed below:

Bog Spavin - A soft filling of the natural depression on the inside of the front of the hock.

Bone Spavin - A bony enlargement on the inside and front of the hock where the base of the hock tapers into the cannon bone of the lower leg. Bone spavin is an inheritable weakness and one of the most destructive conditions affecting a horse's usefulness. The lameness is most evident when the animal is used following rest.

Bowed tendon - A thickened enlargement of any one or all of a group of tendons and ligaments (usually the superflexor tendon, deep flexor tendon and suspensory ligament) which occupy the posterior space of the cannon region between knee and fetlock joint or between hock and fetlock joint.

Bucked shins - A slight swelling anterior to the cannon bone due to a tearing of the periosteum; caused by stress and most common in race horses.

Curb - Enlargement of the hock tendon or ligament on the upper part of the cannon just below the point of the hock; caused by injury or strain.

Fistula - An inflamed condition in the withers region, commonly thought caused by bruising.

Hernia or rupture - The protrusion of any internal organ through the wall of its containing cavity. It usually means passing part of the intestine through an opening in the abdominal muscle. A hernia is a genetic imperfection

Monkey mouth - A hereditary imperfection in how the teeth come together. It is caused by the lower jaw being longer than the upper jaw. These horses will have an underbite.

Osselet - Abnormal bony growth at the fetlock joint.

Parrot mouth - A hereditary imperfection in how the teeth come together. It is caused by the lower jaw being shorter than the upper jaw. These horses will have an overbite.

Ring bone - Bony enlargement near the coronary band which may involve the pastern joint or coffin joint; usually associated with stress or faulty conformation.

Side bone - Loss of flexibility of the lateral cartilages usually in the forefeet caused by ossification; excessive concussion and poor conformation contribute to the condition.

Splint - Calcification between the splint and cannon bones due to injury, stress or faulty conformation.

Thoroughpin - A puffy condition in the hollow of the hock. The puff can be seen mostly on the outside, but is movable when touched. Thoroughpin rarely causes lameness.

Windpuff - A puffy enlargement of the pastern joint or fetlock. The enlargement is a fluid filled distension of the bursa and is more common in the rear legs.