The superior sagittal sinus (also known as the superior longitudinal sinus), within the human head, is an unpaired area along the attached margin of falx cerebri.

Xiphosurans have well-developed circulatory systems, with numerous arteries that send blood from the long tubular heart to the body tissues, and then to two longitudinal sinuses next to the gills.

The inferior sagittal sinus (also known as inferior longitudinal sinus), within the human head, is an area beneath the brain which allows blood to drain outwards posteriorly from the center of the head.

Batson noted "the extensive filling of the vertebral veins, the superior longitudinal sinus, transverse sinus as well as other dural and cerebral veins" following injection of radiopaque material into a superficial venule in the left breast (Batson 1940, Figure 5, page 143).