Dural Venogram

Intracranial Vasculature

      Wherever the cranial and meningeal zones separate, a cleft is created within the thickness of the dural sheet.  Cells facing the lumen become epithelialized, forming a mesothelial lining, and the cleft becomes a dural venous sinus. These sinuses receive the venous drainage of the brain and convey it to extracranial veins whence it returns to the right heart. Most of the dural sinuses leave grooves on the inner surface of the prepared skull. Two, however, have no relation to the skull itself but lie within dural folds: the inferior sagittal sinus runs in the free lower border of the falx cerebri; the straight sinus runs in the intersection between tentorium cerebelli, falx cerebri, and falx cerebelli.

    The figure on the left shows a groove (marked with black dots) formed by the left transverse and sigmoid sinuses (FM indicates the foramen magnum) in the wall of the left posterior cranial fossa.

     The intracranial system of dural venous sinuses (blue vessel in animation below) is continuous with the right and left internal jugular veins through the jugular foramina. This is the principal route of drainage, but there are also communications with veins of the face around the margins of the orbits as well as direct and indirect communications with extracranial veins of the scalp and upper neck. Emissary veins pass directly through emissary foramina in the skull, while other veins link the dural sinuses to veins in the diploл that drain through the outer table into veins of the scalp.  The bilayer dura is represented by the orange and green layers in the animation below.

     The bones of the living skull receive much if not most of their blood supply through fine branches of the numerous so-called “meningeal” arteries (red vessel in the animation below), which are derived from internal carotid, external carotid, and vertebral systems. As a rule, these vessels lie against the inner table of the skull, and their adventitia blends with the endocranium. When the dura is stripped from the skull, the meningeal vessels come away with it, leaving grooves in the surface of the bone (black arrow, below).

Animation showing the disposition of the dura and its relationship to certain intracranial veins.

  Impressions on the inner surface of the skull made by meningeal vessels.

Animation courtesy of T. Van Houten, PhD.  ©2008