Ligamentum sesamoideum distale impar
The distal sesamoidean impar ligament runs from the distal border of the navicular bone to the flexor surface of the coffin bone (P3). It helps stabilize the navicular bone and transfers forces between the navicular bone and P3. Together with the collateral sesamoidean ligaments it forms part of the suspensory apparatus of the navicular bone within the podotrochlear apparatus. Desmitis, enthesopathy, or partial tears are frequently identified on MRI in horses with caudal heel pain / navicular syndrome. Pathology can be primary or secondary to other changes in the DDFT (deep digital flexor tendon), navicular bone, or bursa. The ligament is best evaluated with MRI; ultrasound has limited access.
Common MRI finding in podotrochlear disease. Often concurrent with DDFT or navicular-bone lesions. Treatment is usually medical and part of overall podotrochlear management (rest, shoeing, medication, regenerative therapies).
## Overview Coffin joint disease refers to osteoarthritis or other pathology of the distal interphalangeal joint. It is a common cause of foot lameness in performance horses. Signs range from mild sh
## Overview Deep digital flexor tendon (DDFT) tendinopathy encompasses degenerative or traumatic injury to the tendon, most commonly where it courses over the navicular bone or in the pastern. It pro
Heel pain that does not fully respond to standard treatments may involve the impar ligament; advanced imaging is often required for a complete diagnosis. Follow rehabilitation recommendations carefully.
## Overview Coffin joint disease refers to osteoarthritis or other pathology of the distal interphalangeal joint. It is a common cause of foot lameness in performance horses. Signs range from mild shortened stride and poor performance to marked lameness. Forelimbs are more often affected than hindlimbs. ## Causes Repetitive concussion, conformational faults, prior trauma, or developmental joint disease. Navicular bone changes frequently coexist. ## Diagnosis Lameness examination, distal limb flexion, and diagnostic analgesia. Radiographs show osteophytes, joint-space narrowing, or enthesophytes. Advanced imaging further characterizes cartilage and subchondral bone. ## Treatment Intra-articular corticosteroids, biologics, or viscosupplements; systemic anti-inflammatories; corrective shoeing; and workload modification. Prognosis is guarded to fair depending on severity. ## Recovery and Prognosis Many horses remain useful with management. Advanced disease limits athletic longevity. ## Prevention Balanced shoeing, appropriate footing, and early treatment of foot imbalances. Signs include: foot lameness; shortened stride; positive distal limb flexion; occasional coffin joint effusion; poor performance
## Overview Deep digital flexor tendon (DDFT) tendinopathy encompasses degenerative or traumatic injury to the tendon, most commonly where it courses over the navicular bone or in the pastern. It produces chronic or intermittent forelimb lameness and is a major component of podotrochlear syndrome. ## Causes Repetitive strain, navicular bone interaction, and age-related degeneration. Acute overload can initiate or worsen lesions. ## Diagnosis Lameness examination, nerve blocks, and imaging. Ultrasound evaluates the pastern region; MRI is useful for assessing lesions within the hoof; CT can also identify some DDFT lesions. ## Treatment Rest, controlled rehabilitation, shoeing changes, anti-inflammatories, and regenerative or surgical therapies in selected cases. ## Recovery and Prognosis Variable. Mild lesions often improve; severe or chronic tendinopathy limits long-term athletic use. ## Prevention Appropriate conditioning and early attention to foot pain. Signs include: chronic or intermittent forelimb lameness; positive palmar digital nerve block; shortened stride; pointing; worse on hard surfaces or circles
Common MRI finding in podotrochlear disease. Often concurrent with DDFT or navicular-bone lesions. Treatment is usually medical and part of overall podotrochlear management (rest, shoeing, medication, regenerative therapies).
Heel pain that does not fully respond to standard treatments may involve the impar ligament; advanced imaging is often required for a complete diagnosis. Follow rehabilitation recommendations carefully.
See the Distal Sesamoidean Impar Ligament on our interactive 3D horse model. Open 3D Model