Quittor is a term used to describe chronic infection of the medial or lateral collateral cartilage of the distal phalanx in the horse. This condition is characterized by local inflammation and necrosis of the affected cartilage, with subsequent formation of draining tracts proximal to the coronary band.
The infection is usually caused by a wound, and the horse often presents with moderate to severe lameness and a history of chronic or recurrent drainage.