A distension of the subtendinous calcaneal bursa (between the calcaneus and the end of the achilles tendon (gastrocnemius tendon).

The forelimb includes the scapula, the humerus, the radius and ulna, the carpal bones, the metacarpal bones and the phalanges. It bears 55% of the horse's bodyweight. It has no bony attachment to the rest of the skeleton - it is attached to the trunk only by strong fibrous connective tissue and muscles.

A section of the forelimb including the carpus, the metacarpus and the three phalanges.

The limb that extends from the pelvis to the ground, equivalent to the human leg. 

The section of hindlimb from the hock to the hoof.

Knock-kneed / carpusvalgus: a conformational fault of the forelimbs when viewed from the front. An imaginary line dropped from the shoulder passes through the lateral portion of the carpal joint; the carpal deviates medially.

A jointed appendage used for locomotion. 

The central axis of a limb when seen from the front or from the side.

Conformational fault of the limbs when viewed from the front and/or the side. The axis af a limb deviates from what is considered normal. The normal stance and limb conformation is defined using plumb lines (vertical lines between certain anatomical features and the ground).

The passive stay apparatus of the frontlimb enables a horse to rest while standing and use a minimal amount of muscular energy to do so. Instead of using muscles to stabilise joints, this function is performed by tendons and ligaments which do not fatigue to the same extent. The shoulder joint is prevented from flexing through the M. biceps, the elbow is fixed in extension by the M. triceps. A tendon (Lacertus fibrosus) which effectively extends out of the biceps tendon and the forearmfasciainserts below the carpal joint and locks this in extension. The carpal, fetlock and pastern joints are prevented from overextension by the tension of the flexor tendons and the suspensory ligament.

A gait abnormality seen during the swing phase of a limb. The limb's protraction phase is shortened and disturbed due to mechanical or pain related factors.

A type of lameness where maximal pain is experienced during the supporting phase of the affected limb. A supporting limblameness is often an indication of a problem in the distal portions of the limb, as the increase in pressure during weight-bearing leads to pain in the affected structure.

The overall position and the course of the limb axis compared to plumb lines (vertical lines running from specific anatomical landmarks to the ground).

A congenital or acquired deviation in the positioning of a limb or parts thereof. The axes of the limb are compared to ideals (which run verticaly to the ground in the form of plumb lines dropped from specific anatomical landmarks), deviations from this ideal or norm can be visible from the front, the back or the side.

The passive stay apparatus in the horse's hindlimb allows the horse to stand using minimal muscular energy. 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 second element is the reciprocal apparatus which dictates that the stifle, the hock and the fetlock joints always flex and extend synchronously, so immobilisation of the stifle will also lock the hock and the fetlock in position. This system allows the horse to rest a large portion of the weight of its hindquarters on the 'fixed' hindlimb and rest the collateralhindlimb.