Exit point of the external nasal nerve- cadaveric study

This study aims to confirm how the external nasal nerve exits from the internal surface of the nasal bone to the dorsum of the nose and to determine the exact point of nerve emergence by macroscopic examination. Twenty external nasal nerves of both sexes from the elderly and adult age groups were dissected. The exit point of the external nasal nerve, the width of the nasocartilaginous joint, and the inferior border of the nasal bone from the midline to the nasomaxillary suture were measured. The nerve was classified according to its branching pattern. In this study, in the elderly group, the external nasal nerve enters the dorsum of the nose through the pyriform ligament and exits laterally to the nasocartilaginous joint. But in the adult age group the external nasal nerve exits between the nasal bone and the upper nasal cartilage. We observed mainly three types of nerve but did not find any subtypes or variations in the branching pattern. Among this main classification of nerves, more cases (70%) of type I were observed. However, based on our study, we concluded that the external nasal nerve enters the dorsum of the nose either between the nasal bone and the upper nasal cartilage, or it passes through the pyriform ligament and exits lateral to the nasocartilaginous joint. In rhinoplasty, knowledge about the course, exit point, branching pattern, and variations of the external nasal nerve is unavoidable.