external nasal nerve external nasal nerve the external nasal nerve is a terminal branch of the anterior ethmoidal nerve. the trigeminal nerve (cn v) branches into three nerves, one of which is the ophthalmic nerve, which itself has three branches, one of which is the nasociliary nerve. one of the terminal branches of the nasociliary nerve is the anterior ethmoidal nerve. the anterior ethmoidal nerve divides into a lateral nasal branch and medial nasal branch.the medial nasal branch after giving off sensory branches to the anterior and upper parts of the nasal septum, emerges from beneath the inferior nasal margin to form the external nasal nerve. the external nasal nerve provides sensory innervation to the skin of the external nose to the tip. external nasal nervesensory innervation to the head and neck. the external nasal nerve can be seen emerging from beneath the nasal bone (see tip of black arrow).detailsfromanterior ethmoidal nerveinnervatesexternal skin of nose to the tipidentifierslatinrami nasales externi nervi infraorbitalista98a14.2.01.034ta26212fma52688anatomical terms of neuroanatomy axon pathway trigeminal nerve ophthalmic nerve nasociliary nerve anterior ethmoidal nerve medial nasal branch of anterior ethmoidal nerve external nasal nerve