Equine anatomy

Equine anatomy encompasses the gross and microscopic anatomy of horses, ponies and other equids, including donkeys, mules and zebras. While all anatomical features of equids are described in the same terms as for other animals by the International Committee on Veterinary Gross Anatomical Nomenclature in the book Nomina Anatomica Veterinaria, there are many horse-specific colloquial terms used by equestrians.

External anatomy

Back: the area where the saddle sits, beginning at the end of the withers, extending to the last thoracic vertebrae (colloquially includes the loin or "coupling", though technically incorrect usage)

Barrel: the body of the horse, enclosing the rib cage and the major internal organs

Buttock: the part of the hindquarters behind the thighs and below the root of the tail

Cannon or cannon bone: the area between the knee or hock and the fetlock joint, sometimes called the "shin" of the horse, though technically it is the third metacarpal

Chestnut: a callosity on the inside of each leg

Chin groove: the part of the horse's head behind the lower lip and chin, the area that dips down slightly on the lower jaw; area where the curb chain of certain bits is fastened

Coupling: see "Loin" below

Coronet or coronary band: the ring of soft tissue just above the horny hoof that blends into the skin of the leg

Crest: the upper portion of the neck where the mane grows

Croup: the topline of the hindquarters, beginning at the hip, extending proximate to the sacral vertebrae and stopping at the dock of the tail (where the coccygeal vertebrae begin); sometimes called "rump"

Dock: the living part of the tail, consisting of the coccygeal vertebrae, muscles and ligaments. Sometimes used colloquially to refer to the root of the tail.

Elbow: The joint of the front leg at the point where the belly of the horse meets the leg. Homologous to the elbow in humans

Ergot: a callosity on the back of the fetlock

Face: the area between the forehead and the tip of the upper lip

Fetlock: sometimes called the "ankle" of the horse, though it is not the same skeletal structure as an ankle in humans; known to anatomists as the metacarpophalangeal (front) or metatarsophalangeal (hind) joint; homologous to the "ball" of the foot or the metacarpophalangeal joints of the fingers in humans

Flank: where the hind legs and the barrel meet, specifically the area right behind the rib cage and in front of the stifle joint

Forearm: the area of the front leg between the knee and elbow, consisting of the fused radius and ulna, and all the tissue around these bones; anatomically, the antebrachium.

Forehead: the area between the poll, the eyes and the arch of the nose

Forelock: the continuation of the mane, which hangs from between the ears down onto the forehead of the horse

Frog: the highly elastic wedge-shaped mass on the underside of the hoof, which normally makes contact with the ground every stride, and supports both the locomotion and circulation of the horse

Gaskin: the large muscle on the hind leg, just above the hock, below the stifle, homologous to the calf of a human

Girth or heartgirth: the area right behind the elbow of the horse, where the girth of the saddle would go; this area should be where the barrel is at its greatest diameter in a properly-conditioned horse that is not pregnant or obese

Hindquarters: the large, muscular area of the hind legs, above the stifle and behind the barrel. Can also be used to refer to the back end of a horse.

Hock: the tarsus of the horse (hindlimb equivalent to the human ankle and heel), the large joint on the hind leg

Hoof: the foot of the horse; the hoof wall is the tough outside covering of the hoof that comes into contact with the ground and is, in many respects, a much larger and stronger version of the human fingernail

Jugular groove: the line of indentation on the lower portion of the neck, can be seen from either side, just above the windpipe; beneath this area run the jugular vein, the carotid artery and part of the sympathetic trunk

Knee: the carpus of the horse (equivalent to the human wrist), the large joint in the front legs, above the cannon bone

Loin: the area right behind the saddle, going from the last rib to the croup, anatomically approximate to the lumbar spine

Mane: long and relatively coarse hair growing from the dorsal ridge of the neck

Muzzle: the chin, mouth, and nostrils of the face

Pastern: the connection between the coronet and the fetlock, made up of the middle and proximal phalanx

Poll: commonly refers to the poll joint at the beginning of the neck, immediately behind the ears, a slight depression at the joint where the atlas (C1) meets the occipital crest; anatomically, the occipital crest itself is the "poll"

Root of the tail or root of the dock: the point where the tail is "set on" (attached) to the rump; Sometimes also called the "dock"

Shoulder: made up of the scapula and associated muscles, runs from the withers to the point of shoulder (the joint at the front of the chest, i.e. the glenoid); the angle of the shoulder has a great effect on the horse's movement and jumping ability, and is an important aspect of equine conformation

Splints: bones found on each of the legs, on either side of the cannon bone (8 total); partially vestigial, these bones support the corresponding carpal bones in the forelimb, and the corresponding tarsal bones in the hindlimb; anatomically referred to as metacarpal/metatarsal II (on the medial aspect (inside)) and IV (on the lateral aspect (outside))

Stifle joint: corresponds to the knee of a human, consists of the articulation between femur and tibia, as well as the articulation between patella and femur

Tail: the long hairs which grow from the dock; may also include the dock The long hairs alone are sometimes called the skirt.