Articulatio metacarpophalangea
The metacarpophalangeal joint (commonly called the fetlock) is the joint between the third metacarpal (cannon) bone and the proximal phalanx. The proximal sesamoid bones form the palmar aspect of the joint. It is a high-motion, high-load joint that experiences significant stress during locomotion and is critical for shock absorption and propulsion. The superficial and deep digital flexor tendons pass behind it, and the suspensory ligament inserts on the sesamoids. Injuries here (sesamoiditis, suspensory branch issues, chip fractures, or osteoarthritis) can alter force transmission down the limb.
Common problems include sesamoiditis, suspensory branch desmitis, chip fractures, and osteoarthritis. Diagnosis uses clinical examination, radiographs, and ultrasound. The joint is frequently involved in racehorse and performance horse lameness.
## Overview Sesamoiditis is chronic inflammation and remodeling of the proximal sesamoid bones from repetitive loading and suspensory ligament traction. It is common in young racehorses and sport hor
Swelling, heat, or lameness localized to the fetlock after hard work should be evaluated promptly. Early imaging improves management decisions.
## Overview Sesamoiditis is chronic inflammation and remodeling of the proximal sesamoid bones from repetitive loading and suspensory ligament traction. It is common in young racehorses and sport horses. Signs include low-grade forelimb lameness, pain on palpation of the sesamoids, a positive flexion test, and enlarged, remodeled sesamoids on radiographs. ## Causes Repetitive strain at the suspensory insertion. ## Diagnosis Radiographs showing sesamoid changes, correlated with clinical signs. Ultrasound or scintigraphy may add information. ## Treatment Rest, anti-inflammatories, and gradual return to work. Shock wave or regenerative therapies are sometimes used. Prognosis for high-level performance is often guarded. ## Recovery and Prognosis Guarded for return to previous athletic level in many cases. ## Prevention Careful training of young horses and early management of suspensory soreness. Signs include: chronic low-grade forelimb lameness; pain on sesamoid palpation; positive flexion test; enlarged remodeled sesamoids on radiographs
Common problems include sesamoiditis, suspensory branch desmitis, chip fractures, and osteoarthritis. Diagnosis uses clinical examination, radiographs, and ultrasound. The joint is frequently involved in racehorse and performance horse lameness.
Swelling, heat, or lameness localized to the fetlock after hard work should be evaluated promptly. Early imaging improves management decisions.
See the Metacarpophalangeal Joint (Fetlock Joint) on our interactive 3D horse model. Open 3D Model