Fetlock
Image:TrimmedLeg.jpg|thumb|Fetlock joint: the joint between the cannon bone and the pastern
Fetlock is the common name in horses, large animals, and sometimes dogs for the metacarpophalangeal and metatarsophalangeal joints.
Although it somewhat resembles the human ankle in appearance, the joint is homologous to the ball of the foot. In anatomical terms, the hoof corresponds to the toe, rather than the whole human foot.
Etymology and related terminology
[Image:Koeten.JPG|thumb|Detail of feather or feathering that covers the fetlock and hoof, seen on many draft breeds]The word literally means "foot-lock" and refers to the small tuft of hair situated on the rear of the fetlock joint.
"Feather" refers to the particularly long, luxuriant hair growth over the lower leg and fetlock that is characteristic of certain breeds.
Formation
A fetlock is formed by the junction of the third metacarpal or metatarsal bones, either of which are commonly called the cannon bones, proximally and the proximal phalanx distally, commonly called the pastern bone.Paired proximal sesamoid bones form the joint with the palmar or plantar distal surface of the third metacarpal or metatarsal bones, and are tightly attached to the proximo-palmar or -plantar edge of the proximal phalanx.