Abstract
Background: The posterior cranial fossa is the largest and deepest of the cranial fossae corresponds extracranially with the posterior part of base of skull. Many neurosurgical approaches are limited by the boundaries of the sigmoid, transverse, and transverse–sigmoid junction (TSJ). The knowledge of size and shape of posterior cranial fossa venous sinuses is helpful to neurosurgeons.

Aims and Objectives: The present study was designed to evaluate the morphometry of the posterior cranial fossa venous sinuses.

Materials and Methods: The material for the present study comprised 60 adult human dry skulls of unknown sex available in the Department of Anatomy of two Medical Colleges of the region. Morphometric parameters of grooves for transverse sinus (TS), occipital sinus groove, and sigmoid sinus were noted.

Results: The mean length of grooves for TS, occipital sinus, and sigmoid sinus was 69.5 ± 5.65 mm, 42.62 ± 4.22 mm, and 49 ± 3.87 mm, respectively. Superior sagittal sinus was seen draining into the right side in 83.33% skulls. Width of TS groove was greater on the right side and length of TS groove was more on left side. The position of asterion located below the TSJ was reported in 51.76% skulls. In all the skulls, the asterion was present above the tip of the mastoid process. Incidence of the triple mastoid emissary foramina was 18.33%.

Conclusions: Knowledge of normal range of various parameters of posterior cranial fossa venous sinuses is helpful to neurosurgeons in craniovertebral surgical approaches as well as in posterior cranial fossa surgeries.

Key words: Anatomical Morphometry; Posterior Cranial Fossa; Venous Sinuses