Topographic distribution area of the infraorbital nerve.

The infraorbital nerve (ION) supplies the skin and mucous membranes of the middle portion of the face. This nerve is vulnerable to injury during surgical procedures of mid-face. Severe pain and loss of sense are noted in patients whose infraorbital nerve is either entirely or partially lost after these surgeries. We investigated the distribution area and topography of the ION, about which little is currently known, by dissecting 43 hemifaces of Korean cadavers. The ION produced four main branches, the inferior palpebral, internal nasal, external nasal, and superior labial branches. The inferior palpebral branch was generally bifurcated, giving off a medial and a lateral branch (58.1%). The internal nasal branch ran superior to the depressor septi muscle, along the ala of the nose. It supplied the skin of the philtrum and gave off a terminal branch that supplied the nasal septum and the vestibule of the nose. The external nasal branch was distributed diversely supplying areas between the root and the ala of the nose. The superior labial branch was the largest branch of the ION produced the most subbranches. These subbranches were divided into the medial and lateral branches depending upon the area that they supplied.