The trigeminal nerve is the fifth cranial nerve and is primarily responsible for sensation in the face. It has three main branches: the ophthalmic, maxillary, and mandibular nerves, which transmit sensory information from different areas of the face to the brain. This nerve also plays a role in motor functions, particularly in controlling the muscles used for chewing. In addition to sensation, the trigeminal nerve is involved in reflex actions such as blinking and the corneal reflex. Disorders affecting this nerve can lead to conditions like trigeminal neuralgia, which causes severe facial pain. Understanding its function is essential for diagnosing and treating facial pain and sensory disorders.