The mandibular nerve is one of the three main branches of the trigeminal nerve, which is responsible for sensation in the face. It primarily provides sensory innervation to the lower jaw, including the lower lip, chin, and parts of the ear. Additionally, it supplies motor functions to the muscles involved in chewing. This nerve divides into several smaller branches, including the inferior alveolar nerve, which innervates the lower teeth, and the lingual nerve, which provides sensation to the tongue. Understanding the mandibular nerve is important in dentistry and oral surgery, as it plays a crucial role in pain management and anesthesia.