A new approach for perineural injection of the lateral palmar nerve in the horse.
OBJECTIVE
To evaluate the accuracy of a new technique for perineural injection of the lateral palmar nerve and to determine frequency of inadvertent injection into the carpal synovial sheath with this technique.


METHODS
Prospective experimental study.


METHODS
Thirty equine cadaver forelimbs.


METHODS
Each of 3 clinicians injected 0.5 mL of a 1% aqueous solution of new methylene blue as a marker at the medial aspect of the accessory carpal bone of 10 limbs. Immediately after each injection, the lateral palmar nerve was identified by dissection of and inspected for proximity of dye, and the carpal synovial sheath was inspected for the presence of dye.


RESULTS
New methylene blue solution was observed to surround the nerve (29 limbs) or to lie within 2 mm of it (1 limb). Dye was not found in the carpal synovial sheath of any specimen.


CONCLUSIONS
Using this technique, perineural injection of the lateral palmar nerve can be consistently achieved, and the carpal synovial sheath is unlikely to be penetrated by the needle during the procedure.


CONCLUSIONS
The technique described provides an accurate and simple method for perineural injection of the lateral palmar nerve proximal to the origin of its deep branch. This technique can be used to anesthetize the lateral palmar nerve for diagnosis of pain originating in the palmaroproximal aspect of the metacarpus without risk of inadvertently desensitizing structures within the carpal synovial sheath.
Castro
Fernando A
FA
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA. fcastro@ucdavis.edu
Schumacher
James S
JS
Pauwels
Frederik
F
Blackford
James T
JT
D000818:Animals; D002102:Cadaver; D002350:Carpus, Animal; D005552:Forelimb; D006736:Horses; D007270:Injections, Intra-Articular / Q000662:veterinary*; D008751:Methylene Blue / Q000031:analogs & derivatives; D009407:Nerve Block / Q000379:methods / Q000662:veterinary*; D011446:Prospective Studies; D013583:Synovial Membrane / Q000187:drug effects
C035184:new methylene blue; D008751:Methylene Blue