Carpus (Knee)
Introduction
The knee (carpus) contains three different joints, the radiocarpal joint, the middle carpal joint and the carpometacarpal joint. The radiocarpal joint is between the radius and the first row of small carpal bones, the radial, intermediate and ulna carpal bones. The middle carpal joint is between this row of carpal bones and a second row beneath, the second, third and fourth carpal bones. The third joint is the carpometacarpal joint and is between this second row of bones and the canon. The accessory carpal bone is at the back of the knee. There are several tendons that pass over the front of the knee, some of which lie within their own tendon sheaths. At the back of the knee is the carpal canal where the flexor tendons run. Lameness involving the knee is relatively common and is a common site for arthritis.