Análise topográfica da relação entre o nervo facial e a borda posterior do ramo da mandíbula

Abstract

The inferior alveolar nerve block (IANB) is one of the most commonly used anesthetic techniques in dentistry, but it has high failure rates due to anatomical variations and the difficulty in locating the neurovascular bundle. In addition to analgesic failure, the technique is subject to various risks, one of which is the deposition of the anesthetic near the posterior border of the mandibular ramus, a region where branches of the facial nerve (VII cranial nerve) emerge, which may cause transient paralysis of the muscles innervated by it. The objective of this study was to analyze the topographic relationship between the posterior margin of the mandibular branch and the portion of the facial nerve located posterior to the parotid gland, using descriptive, basic, and quantitative anatomical dissection. Seven formalin-fixed hemicrania from the collection of the Department of Anatomy at UFU were analyzed, using a digital caliper to measure the anteroposterior and superior-inferior distances between the structures, as well as to record possible anatomical variations. The results showed distances ranging from 5 mm to 13 mm in the anteroposterior direction and from 18 mm to 27 mm in the superoinferior direction. It is concluded that there is a close relationship between the posterior border of the mandible and the facial nerve, highlighting the risk of accidental anesthesia of the VII cranial nerve during the NAI block and the importance of anatomical knowledge of the analyzed structures for performing anesthetic blocks in dentistry.