Sites of Anesthetic Block of the Lateral and Medial Palmar Metacarpal Nerves in Equines of Indeterminate Breed

Background: Local anesthesia blockage at equines claudication diagnosis besides favoring the beginning of the therapy and relieving patient’s pain, it allows the identification of the specific affected region and its origin, however, if it is done incorrectly (by improper volume of anesthetics application and/or mistakenly nerve identification due to the lack of anatomic referential) it may cause inflammation, infection or even tissue necrosis. The aim was describing anatomically lateral and medial palmar metacarpal nerves in equines to improve diagnostic anesthetic block techniques on four metacarpophalangeal articulation joints of the specie.Materials, Methods & Results: A number of 20 thoracic limbs from 10 equines of indeterminate breed were used to be fixated in 10% phormaldehyde and with a marked arterial system by water solution of red dyed latex. The structures were identified by dissection, and their denomination bases on Nomina Anatomica Veterinaria (N.A.V.) by the International Committee on Veterinary Gross Anatomical Nomenclature. The study had been approved by the Board of Ethics in Animal Use of the University Center of Patos de Minas (UNIPAM), protocol n° 18/17. The lateral and medial palmar metacarpal nerves have been observed in all of the specimens originated from the deep branch of lateral palmar nerve, immediately distal to the intercarpal articulation. After its origin, the first nerve stretched ipsilaterally from the common trunk, whilst the second nerve positioned counter-lateral manner after superficially crossing the interosseus muscle. Both penetrated at the level of the mid third of the referred muscle and the metacarpal bone III and, assumed respectively a parallel medial position to the metacarpal bone IV and lateral to the metacarpal II, being intimately associated to the palmar face of the metacarpal bone III. Distally, those nerves emerged from a palmar position to a lateral and medial to the distal extremity of the metacarpal bones, corresponding and adjacent to the metacarpophalangeal articulation palmar recession, where they had finally ramified to partially innervate the associated articular capsule and the subcutaneous tissue of the region.Discussion: The lateral and medial palmar metacarpal nerves present similar origin and disposition to the above described, however, besides largely mentioned in literature, we point out here as recommended by N.A.V., no use of terms like axial and abaxial as position indicators for eq