Handbook of Breadmaking Technology

Abstract

Results of recent studies in the horse indicate that anaesthesia of the palmar digital nerves causes desensitization of the entire sole, the navicular apparatus, and the entire distal interphalangeal (DIP) joint Anaesthesia of the palmar digital nerves may improve the gait of some horses that are lame because of pain in the proximal interphalangeal joint especially if the block is performed proximal to the junction of the nerve and the cartilages of the foot. For most horses the navicular apparatus is desensitized by administering local anaesthetic solution into the DIP joint. Anaesthesia of the DIP joint also causes desensitization of the toe region sole of the foot even when a small volume (i.e., 6 mL) of local anaesthetic solution is administered and desensitization of the entire sole when a large volume (i.e., 10 mL) is administered. Anaesthesia of the navicular bursa is the most specific diagnostic block of the horse's foot because it only results in desensitization of the navicular apparatus and the toe region of the sole. Many horses that are lame because of lesions in the deep digital flexor tendon within the foot show little improvement in gait after a palmar digital nerve block but all go sound after an abaxial sesamoid nerve block This indicates that a portion of the deep digital flexor tendon within the foot receives its sensory supply from branches of the medial and lateral palmar digital nerves that are given off proximal to the site of a palmar digital nerve block intrathecal analgesia of the digital flexor tendon sheath may be useful for localisation of lameness that is unchanged after analgesia of the palmar digital nerves, but resolves after an abaxial sesamoid nerve block.