Tarsal joint block sites, horse

Tarsal joint block sites in a horse. 1. Tarsometatarsal joint: A 22‑gauge, 2.5‑cm (1‑inch) needle is inserted to its hub in the direction of the arrow, just proximal to the head of the fourth metatarsal bone (MTIV). 2. Distal intertarsal joint: A 25‑gauge, 1.6‑cm (5/8‑inch) needle is inserted to its hub, if possible, perpendicular to the skin surface, either through or near the cranial margin of the cuneal tendon. 3. Tibiotarsal joint: A 21‑gauge, 3.8‑cm (1½‑inch) needle can be inserted perpendicular to the skin, in either the plantarolateral pouch or the dorsomedial pouch. This joint block is aided, and the pouches are more easily identified, when tibiotarsal effusion is present; the horse in this photograph does not have joint effusion.