Thoroughpin is a swelling of the tendon sheath around the deep digital flexor tendon of the hind leg as it passes around the hock. It therefore is found just in front of the Achilles tendon and just above the point of the hock. Thoroughpin is normally associated with poor conformation of the hocks which puts extra strain on this tendon area. It does not normally need treatment and the swelling tends to go down with time. Applications which reduce swelling like DMSO can sometimes be used to reduce swelling.