Fig. 3From: Retrosigmoid approach assisted by high-resolution computed tomography: a cost-effective technique to identify the transverse and sigmoid sinus transitionThe course of mastoid emissary vein and slice B. The course of mastoid emissary vein can be traced through the continuous CT images (a–c). The slice B (d) should reveal the mastoid emissary foramen and the locations of point γ and point δ. The distance between point δ and the mastoid emissary foramen should be measuredBack to article page