Pontos de bloqueio dos nervos metacarpais palmares lateral e medial em equinos sem raça definida

Abstract

Locomotion problems are the main complaints at veterinarian practices within equine breeding management, once metacarpophalangeal articulation comes out reaching the highest rates of lesions. Local anesthesia blockage at 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 horses, to improve diagnostic anesthetic block techniques on four metacarpophalangeal articulation joints of the specie. A number of 20 foots from 10 horses of unidentified 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 Veterinary Anatomical Nomenclature (V.A.N.). This study was approves by Animal Ethical Committee of the University Center of Patos de Minas, under protocol number 18/17. Lateral and medial palmar metacarpal nerves were observed in all specimens originated from the deep branch of lateral palmar nerve, immediately distal to the intercarpal articulation. From its origin afterwards, the first nerve extended ipsilaterally from the common digital extensor tendon, while the second nerve has positioned contralaterally after crossing the interossei muscle. Both penetrated to the level of the mid third of the referred muscle and the metacarpal boné III and, assumed respectively a parallel medial position to the metacarpal bone IV and lateral to the metacarpal II. Distally, those nerves emerged from a palmar position to a lateral and medial to the distal extremity of the metacarpal bones, corresponding and adjacente to the metacarpophalangeal articulation palmar recession, where finally they ramify. 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 V.A.N., no use of terms like axial and abaxial as position indicators for equine. As a part of block anesthetic diagnosis of four metacarpophalangeal articulation points, it is hereby indicated for the studied nerves desensitization, should be palpated the distal extremities of the metacarpal bones IV and II. After the identification, using thumb located from the extremity at proximal direction way, introduce the needle bilaterally for 1.5cm downright between the above mentioned metacarpal bones and the interossei muscle, being these latter and the flexor muscle tendons drawn in the palmar direction, therefore avoiding traumas in the structures nearby and improving the applied technique.