Anatomy and Common Injuries of the Equine Forelimb
Anatomy of the Forelimb
An understanding of equine anatomy is essential in veterinary practice to ensure that an accurate diagnosis is made and, therefore, that the correct management option is selected. HINKLE
Normal Anatomy The forelimb (also known as the thoracic limb) in the horse is adapted for extension and ground covering WEB. This limb carries 55 to 60 percent of the horse’s body weight, and a large proportion of the rider’s weight as well WEB.
The shoulder girdle (scapula, coracoid, clavicle) is greatly reduced in the equine limb. The clavicle is only present as a fibrous strip in the brachiocephalicus muscle. WEB
Scapula: Wide, semilunar scapular cartilage Palpable tuber on the scapular spine No acromion
Humerus: Short and thickened Has a deep bicipital groove
Radius and Ulna Only the radius supports the humerus at the elbow joint The ulna is fused to the radius Proximally, the ulna reaches to the fifth rib
Carpal Bones The proximal row of carpal bones consists of the radial, intermediate, ulnar and accessory carpal bones (medial to lateral) The distal row consists of the first, second, third and fourth carpal bones. The first bone is small and not consistent
Metacarpal (MC) Bones Only MC2, MC3, MC4 are present MC2 and MC4 are reduced and are also known as splint bones. They are connected to MC3 by fibrous tissue MC3 (also called the “cannon bone”) is well developed and carries all of the horse’s weight
Phalanges (P) The proximal phalanx (P1) is the longest of the phalanges The middle phalanx (P2) is half the length of PI. It has a large flexor tuberosity to which the superficial digital flexor tendon attaches The distal phalanx (P3 or the “coffin bone”) is a spongy bone to which the deep digital flexor tendon attaches
Sesamoid Bones: The proximal and distal sesamoid bones are clinically important. The proximal bones articulate with M3 while the distal bone (i.e. the navicular) lies within the hoof and contacts the middle and distal phalanges. WEB
