The brainstem is located below the brain, between the spinal cord and the mesencephalon, and is the part of the spinal cord that extends into the cranial cavity. It mainly includes the midbrain, the pons, and the medulla oblongata, and there are 12 pairs of cranial nerves, all of which have different functions, including motor and sensory. Different parts of the brainstem have different symptoms when their nerves and functions are damaged.1. Midbrain: There are the motoneurotic nerve and the talocrural nerve. If it is a midbrain injury, it will cause tetraplegia and the patient can only express his will through eye movements, such as blinking. 2. Brain bridge: the abducens nerve, trigeminal nerve, facial nerve and vestibular position auditory nerve. Injuries to the cerebral bridge can result in facial nerve paralysis, trigeminal nerve sensory abnormalities, dizziness, hearing loss, etc., and also abduction dysfunction; 3, medulla oblongata: there are the glossopharyngeal nerve, vagus nerve, hypoglossal nerve and paraglossal nerve. Injury to the medulla oblongata usually causes difficulty in swallowing, choking and coughing. In severe cases, there is even respiratory and cardiac arrest, requiring ventilator-assisted breathing. The brainstem is relatively small, but its function is very important. If an injury occurs, seek immediate medical attention, and the earlier treatment is performed after a clear diagnosis, the better the prognosis will be.