THOMAS K. HUGHES, MA, VetMB, CertES(Orth), EHUD ELIASHAR, BSc, DVM, Diplomate ECVS, and ROGER K. SMITH, MA, VetMB, PhD, DEO, Diplomate ECVS

Veterinary Surgery 36:760–764, 2007

Objective: To examine the anatomic relationship of the deep branch of the lateral plantar nerve (DBLPN) with structures of the proximal metatarsal region, and to define the anatomic location of a solution injected using a single injection technique for diagnostic analgesia of the proximal suspensory ligament (PSL).

Study Design: Descriptive study.

Animals: Cadaveric equine pelvic limbs (n=29).

Methods: The proximal metatarsal region of both pelvic limbs (n=5 horses, 10 limbs) was dissected and measurements were made of anatomic structures relative to the head of the 4th metatarsal bone (HMT4). A single injection technique was used to inject dye 15mm distal to the HMT4, axial to the MT4 at a depth of 25mm in each limb from 10 equine cadavers (19 limbs). Hindlimbs were dissected and the position of the dye was recorded.

Results: DBLPN branched from the lateral plantar nerve (LPN) at a mean distance of 30mm proximal to the HMT4 and entered the PSL at a mean distance of 17mm distal to the HMT4. A 2nd DBLPN was observed in 1 of 10 dissected limbs. Blue dye surrounded the DBLPN in 18 limbs (95%).

Conclusions: A single injection technique was likely to have resulted in desensitization of the DBLPN in 18 of 19 limbs (95%).

Clinical Relevance: This technique provides a reliable method using a single needle puncture for perineural analgesia of the DBLPN for diagnosis of proximal suspensory desmitis of the pelvic limb with a minimal risk of inadvertently desensitizing structures within the tarsal sheath and the tarsometatarsal joint.