Cuneus ungulae
The frog is the V-shaped, elastic, wedge-like structure on the ground surface of the equine foot that lies between the bars and forms the central portion of the palmar/plantar foot. It is composed of modified epidermis with a high water content, allowing it to deform and recoil with each step. A broad, well-developed frog in ground contact contributes to shock absorption, traction, and expansion of the hoof capsule. It works closely with the digital cushion: when the foot lands, the frog compresses the cushion, helping dissipate impact forces and contributing to the hemodynamic pump that assists venous return from the foot. Atrophy or disease of the frog (often secondary to conformational issues, chronic lameness, or lack of ground contact) reduces its functional contribution and predisposes to thrush. Thrush is a bacterial infection of the frog sulci that thrives in moist, anaerobic conditions and can range from a mild black discharge to deep invasion of the digital cushion.
Thrush is common and usually managed with cleaning, topical antiseptics, and improved environment and farriery. Severe thrush can cause lameness if it invades sensitive tissues. Frog atrophy is associated with contracted heels and increased risk of caudal heel pain.
Keep the frog clean and the environment as dry as practical. A foul-smelling black discharge in the sulci is thrush; clean it and address moisture and farriery. Encourage frog ground contact through appropriate trimming. Sudden heel pain or deep frog lesions need veterinary attention.
Thrush is common and usually managed with cleaning, topical antiseptics, and improved environment and farriery. Severe thrush can cause lameness if it invades sensitive tissues. Frog atrophy is associated with contracted heels and increased risk of caudal heel pain.
Keep the frog clean and the environment as dry as practical. A foul-smelling black discharge in the sulci is thrush; clean it and address moisture and farriery. Encourage frog ground contact through appropriate trimming. Sudden heel pain or deep frog lesions need veterinary attention.
See the Frog on our interactive 3D horse model. Open 3D Model