Twelve pairs of nerves mainly refer to twelve pairs of cerebral nerves, which emanate from the brain and are generally called twelve pairs of cerebral nerves because they are paired left and right. The twelve pairs of nerves are olfactory nerve, optic nerve, oculogyric nerve, trochlear nerve, trigeminal nerve, abducens nerve, facial nerve, local auditory nerve, linguopharyngeal nerve, vagus nerve, collateral nerve, and hypoglossal nerve, which are mainly distributed in the head and face, among which the vagus nerve can also be distributed to the thorax and abdomen and internal organs. For example, the olfactory nerve is generally related to the sense of smell, the optic nerve is related to vision, the motoneurotic nerve, the trochlear nerve and the abducens nerve are directly related to eye movement and eyelid elevation, and the trigeminal nerve is clinically used, which is divided into three branches.