Distribution of the mylohyoid nerve: anatomical variability and clinical implications

The mylohyoid nerve is a branch of the mandibular division of the trigeminal nerve that provides motor supply to the mylohyoid and digastric muscles. Accessory innervation to the pulps of both anterior and posterior mandibular teeth by the sensory component of this nerve has been proposed to be one possible anatomical variation leading to failure of an inferior alveolar nerve block. The aim of this study was to trace the path of the mylohyoid nerve, from its origin in the infratemporal region to its terminal branches, in six human cadavers. Dissections of sagittally-sectioned heads were performed using both medial and submandibular approaches. The anatomy of the mylohyoid nerve was variable in terms of its level of branching, course through the mylohyoid groove or canal, branch numbers to the mylohyoid and digastric muscles, and terminal branching in the submental region. In all cases the mylohyoid nerve was seen to pass down the medial surface of the ramus behind the sphenomandibular ligament.