An Anatomic Study on the Overlap Patterns of Structural Components in the Keystone Area in Noses of Koreans

OBJECTIVES: The keystone area has critical importance in maintaining the stability of the nasal dorsum. However, overlap patterns between structural components in the keystone area have rarely been studied, especially in the noses of Koreans. METHODS: Dissections were performed on 18 cadaveric noses. The length and width of the structural components in the keystone area were measured. The shape of the caudal margin of the nasal bone and the overlap patterns between the upper lateral cartilage and the nasal bone were classified. RESULTS: The shape of the caudal margin of the nasal bone were classified as follows: type A, curvilinear margin; type B, paramedian retractions or "M" shape; type C, elongated midline; and type D, retracted midline. The overlap area between the upper lateral cartilage and the nasal bone was classified as follows: type Ao, crescent shape; type Bo, short midline extension; and type Co, long midline extension. The cephalocaudal length of the overlap area between the upper lateral cartilage and the nasal bone was 4-10 mm (mean, 7 mm) in the midline, and 0-7 mm (mean, 3.1 mm) in the paramedian area. The overlap width of the upper lateral cartilage with the nasal bone was 8-14 mm (mean, 9.7 mm). CONCLUSION: The overlap pattern of the structural components in the keystone area is variable. Therefore, a thorough understanding and a cautious evaluation of the relationships of these components before and during surgery is important in performing safe and effective nasal procedures.