Distal intertarsal and tarsometatarsal joints in the horse: communication and injection sites.

One hundred three equine hocks, obtained from the postmortem room, were used to study the communication and injection of material into the distal intertarsal and tarsometatarsal joints. Excluding the hocks with fused central and 3rd tarsal bones, in 8.3% of hocks injected with low (clinical) pressure and in 23.8% injected with high pressure, the distal intertarsal and tarsometatarsal joints communicated by dissection of the material through 2 internal spaces: the tarsal canal and the space between the combined tarsal bones 1 and 2 tarsal bone 3. A "pop" sometimes felt when high pressure was used did not necessarily indicate that a communication between the 2 joints had been established. The distal intertarsal joint was best punctured medially through the proximal part of the gap between the combined tarsal bones 1 and 2, tarsal bone 3, and the central tarsal bone. The tarsometatarsal joint was most reliably punctured plantarolaterally between the head of the 4th metatarsal and 4th tarsal bones.