This is the groove that houses the occipital dural venous sinus. It is situated in the median plane coursing from the internal occipital protuberance to the posterior edge of the foramen magnum. To its edges attach the falx cerebelli.

Sulcus is Latin for groove or a long, shallow, open channel in the bone. Occiput is Latin for the back portion of the head. It is derived from the prefix ob- meaning on, against, or opposite, combined with the Latin caput meaning head. Sinus is Latin for a curve, fold, bay, or gulf. In anatomy it can describe anything from a large, hollow cavity to a concave groove-like channel.