The " occipital ", the largest of the four, which is confined to the occipital bone, and opens either externally into the occipital vein, or internally into the transverse sinus or into the confluence of the sinuses ( torcular Herophili ).
22.
It has been proposed that a positive biofeedback loop may exist, where raised ICP ( intracranial pressure ) causes venous narrowing in the transverse sinuses, resulting in venous hypertension ( raised venous pressure ), decreased CSF resorption via arachnoid granulation and further rise in ICP.
23.
It is perforated by numerous foramina ( holes ); one of these, of large size, situated near the posterior border, is termed the mastoid foramen; it transmits a vein to the transverse sinus and a small branch of the occipital artery to the dura mater.
24.
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 ).
25.
On December 31 it was announced that the clot was behind her ear near her brain, specifically a right transverse sinus venous thrombosis, that she was being treated with anticoagulants, that she had not suffered any neurological damage, and that she was expected to make a full recovery.
26.
Behind either condyle is a depression, the condyloid fossa, which receives the posterior margin of the superior facet of the atlas when the head is bent backward; the floor of this fossa is sometimes perforated by the condyloid canal, through which an emissary vein passes from the transverse sinus.
27.
It is attached, behind, by its convex border, to the transverse ridges upon the inner surface of the occipital bone, and there encloses the transverse sinuses; in front, to the superior angle of the petrous part of the temporal bone on either side, enclosing the superior petrosal sinuses.
28.
In the upper part of the internal occipital crest, a small depression is sometimes distinguishable; it is termed the vermian fossa since it is occupied by part of the Transverse grooves, one on either side, extend from the internal occipital protuberance to the lateral angles of the bone; those grooves accommodate the transverse sinuses, and their prominent margins give attachment to the tentorium cerebelli.
29.
The exact relation of the parts to one another in the jugular foramen is as follows : the inferior petrosal sinus lies medially and anteriorly with the meningeal branch of the ascending pharyngeal artery, and is directed obliquely downward and backward; the transverse sinus is situated at the lateral and back part of the foramen with a meningeal branch of the occipital artery, and between the two sinuses are the glossopharyngeal, vagus, and accessory nerves.
30.
Each transverse sinus passes lateralward and forward, describing a slight curve with its convexity upward, to the base of the petrous portion of the temporal bone, and lies, in this part of its course, in the attached margin of the tentorium cerebelli; it then leaves the tentorium and curves downward and medialward ( an area sometimes referred to as the sigmoid sinus ) to reach the jugular foramen, where it ends in the internal jugular vein.
