Os tarsale III (T3)
The third tarsal bone (T3) is the largest bone in the distal tarsal row. It articulates proximally with the central tarsal bone and distally with the third metatarsal (cannon) bone. Along with T1+T2 and the central tarsal bone, it is commonly affected by bone spavin (distal tarsal osteoarthritis).
Bone spavin is a common cause of hindlimb lameness in performance horses. Diagnosis uses clinical examination, flexion tests, and radiographs. Management is usually medical and includes rest, medication, and shoeing adjustments. Intra-articular treatments are sometimes used.
## Overview Bone spavin is osteoarthritis (degenerative joint disease) of the distal tarsal joints, principally the distal intertarsal and tarsometatarsal joints. Repeated compression and rotation da
## Overview Slab fractures of the third carpal bone (C3 or T3 in some nomenclature) are full-thickness fractures, most often frontal plane through the radial facet. They are a classic racehorse injur
## Overview Distal tarsal osteoarthritis, commonly called bone spavin, is degenerative joint disease of the lower hock joints (distal intertarsal and tarsometatarsal joints). It is a frequent cause o
Chronic hock stiffness or reduced hindlimb engagement should be evaluated. Correct shoeing and balanced work help manage many cases of bone spavin.
## Overview Bone spavin is osteoarthritis (degenerative joint disease) of the distal tarsal joints, principally the distal intertarsal and tarsometatarsal joints. Repeated compression and rotation damage cartilage, narrow the joint spaces, and stimulate new bone formation. The result is progressive hind-limb lameness that is one of the most common causes of performance limitation in sport horses. ## Causes Repetitive concussion, conformational faults (straight or sickle hocks), and athletic activities that heavily load the hocks (jumping, dressage, western performance) are the main drivers. Mineral imbalances have been suggested but evidence is limited. ## Diagnosis History of gradual hind-limb lameness that may warm out of, positive flexion tests, and a characteristic “stabbing” or short stride are suggestive. Radiographs show joint-space narrowing, sclerosis, and periarticular new bone. Diagnostic analgesia of the distal tarsal joints confirms the source of pain. ## Treatment Non-steroidal anti-inflammatory drugs, intra-articular corticosteroids, corrective shoeing, and workload modification are first-line measures. Chemical or surgical arthrodesis (facilitated ankylosis) can be considered when medical management fails and the goal is pain-free fusion of the low-motion joints. ## Recovery and Prognosis Many horses remain useful with medical management. Complete fusion, whether spontaneous or surgical, can restore comfort. Advanced bilateral disease may ultimately limit athletic career length. ## Prevention Selection for good hock conformation, balanced shoeing, and sensible training progression reduce risk but cannot eliminate it in high-level athletes. Signs include: gradual hindlimb lameness; shortened stride or toe dragging; positive hock flexion test; bony enlargement on the medial lower hock in advanced cases; stiffness after rest
## Overview Slab fractures of the third carpal bone (C3 or T3 in some nomenclature) are full-thickness fractures, most often frontal plane through the radial facet. They are a classic racehorse injury treated by lag-screw fixation. ## Causes High-speed loading. ## Diagnosis Radiographs. ## Treatment Lag screws. ## Recovery and Prognosis Fair to good. ## Prevention Training management. Signs include: acute carpal lameness; effusion; radiographic slab of the third carpal bone
## Overview Distal tarsal osteoarthritis, commonly called bone spavin, is degenerative joint disease of the lower hock joints (distal intertarsal and tarsometatarsal joints). It is a frequent cause of hind-limb lameness in performance horses. Affected horses show stiffness, shortened stride, and positive flexion tests. ## Causes Repetitive loading, conformational faults (straight or sickle hocks), and age-related cartilage wear. ## Diagnosis Lameness examination, hock flexion test, diagnostic analgesia, and radiographs showing osteophytes, joint-space narrowing, or ankylosis. ## Treatment Intra-articular corticosteroids or other medications, systemic anti-inflammatories, corrective shoeing, and workload adjustment. Many horses improve and remain useful. ## Recovery and Prognosis Fair to good for comfort and lower-level work. Advanced cases may require ongoing management. ## Prevention Balanced shoeing and sensible training. Early treatment of stiffness. Signs include: hind-limb stiffness; shortened stride; positive hock flexion; reluctance to collect or engage the hindquarters; radiographic changes in the lower hock joints
Bone spavin is a common cause of hindlimb lameness in performance horses. Diagnosis uses clinical examination, flexion tests, and radiographs. Management is usually medical and includes rest, medication, and shoeing adjustments. Intra-articular treatments are sometimes used.
Chronic hock stiffness or reduced hindlimb engagement should be evaluated. Correct shoeing and balanced work help manage many cases of bone spavin.
See the Third Tarsal Bone (Left) on our interactive 3D horse model. Open 3D Model