Abstract:

Objective　To investigate the quantitative relationships between sigmoid sinus(SS) and anatomic landmarks correlated with SS, and provide anatomic basis for safety in lateral skull base surgery. Methods　40 human temporal bones were obtained and dissected with typical radical mastoidectomy so that the dura mater of middle and posterior cranial fossa, lateral semicircular canal, genu of facial nerve, SS, jugular bulb(JB), mastoid process, stylomastoid foramen, digastric ridge, the posterior wall of external auditory canal(EAC) can be exposed. The distances from SS to neighbouring structures were measured with caliper or electron sliding caliper.　Results　The distance from EAC to anterior border of SS was (1.41±0.32)cm, the distance from lateral wall of SS to lateral wall of mastoid process was (1.02±0.38)cm, the length of the mastoid portion of facial nerve was (1.28±0.13)cm, the distance from the beginning of the mastoid portion of facial nerve to SS was (0.56±0.20)cm, the distance from the end-point of the mastoid portion of facial nerve to SS was (0.62±0.22)cm, the distance from digastric ridge to SS was (0.52±0.18)cm, the distance from stylomastoid foramen to SS was (1.02±0.24)cm.　Conclusion　A statistically significant correlation was found between the distance of the SS to the beginning and the SS to the end-point of the mastoid portion of facial nerve; Comparing the distance of the stylomastoid foramen and the digastric ridge compared to the SS, a proportional and direct relation was found; A significant relationship between the degree of mastoid pneumatization and the morphology of SS was found.

Key words: Lateral skull base, Sigmoid sinus, Applied anatomy