Mastoid Foramen and Superficial Mastoid Canals of Korean Men

Kim, Won Sik; Kim, Soo Il; Kim, Sun; Zheng, Guo Dong; Yang, Eun Jin; Han, Seung Ro

Abstract

The mastoid foramina and the superficial mastoid canals at the mastoid area are well known to have much clinical and anthropological significances. However, few sutdies on these structures were reported. Authors performed this study to analyze those structures of the Korean men, and compared with other populations. The existence, number, location of matoid foramen, distance from the posterior border of the opening of external acoustic meatus were measured. In addition, the existence, shape and the direction of the superficial mastoid canals were investigated. The results were as follows; 1. Among the 67 skulls of Korean men, there was no mastoid foramen on both sides in 1 case. In 10 cases, there was mastoid foramen on right side only, and in 4 cases left side only. In 52 cases (77.6%), there was mastoid foramen on both sides. 2. In the incidence of mastoid foramen, 1 in 27 cases, 2 in 23 cases and 3 in 11 cases on the right side, and 1 in 25 cases, 2 in 22 cases and 3 in 17 cases on the left side were found. 3. 64.0% of mastoid foramina located on the temporal bone, 28.5% were on the occipitomastoid suture, 5.2% were on the occipital bone, 1.9% were on parietomastoid suture, and 1 case on the parietal bone. 4. In the sidedness of mastoid foramen, 1-1 foramen on each side was 15 cases, 2-2 foramina on each side was 10 cases, 1-2 foramina on right-left side was 8 cases, and 0-0 on each side, 2-4 on right-left side, and 4-3 on right-left side were 1 case respectively. 5. The average diameter of mastoid foramen was 2.0+/-0.69 mm, and the distance from the posterior margin of the external acoustic meatus was 33.6+/-3.69 mm. There was no significant differences between right and left sides. 6. The superficial mastoid canals appeared in 23 cases (34.3%), among which 12 cases were on right side and 11 cases were on left side. 14 canals were straight in shape, 2 were grooved, and others were arched, sigmoid or bridged. 21 canals directed toward parietal bone and others directed occipital bone. According to the above results, the existence, number, size and the distance from external acoustic meatus of mastoid foramina, and the incidence, shapes and directions of superficial mastoid canals were much variable. Of course, these variations would have great clinical significances during the neurosurgical and otolaryngeal surgery. These data would contribute to study epigenetic study of minor variations of skull and anthropological study.