phlebologist wrote:uprightdoc wrote:drsclafani wrote:uprightdoc wrote:can we stay on this case please
Basing on these pictures you can say nothing about intracranial sinuses -
Moreover, poor visibility of internal jugular vein at the level of skull base most likely does not represent compression by osseous or fibrotic pathology. Rather, it is a result of collapse of the vein secondary to negative transmural pressure. Transmural pressure is the difference between pressure inside the vessel (due to the blood flow forces) and pressure outside (executed by the tissue surrounding blood vessel). Value of transmural pressure is of great importance in a case of the vein, since most of the veins can collapse (thin wall; the exception are veins like inflamed varicose veins, but this is the other story). Since outside pressure remain constant, the vein can collapse when the pressure inside goes down below the value of external pressure. This can be due to gravitational effects (jugular vein in an upright person, saphenous vein with leg elevated, or cubital veins with hand elevated), but also in a case of low flow through the vein (simplified, since in a case of CCSVI perhaps more complex fluid mechanics principles play a role)
I didn't bring up the sigmoid sinus. Dr. Cummings pointed it out.
Likewise, the superior sagittal sinus drops 5-10 mmHg in the upright position. Despite negative intraluminal pressure it stays open due to the strength of the dura mater. (Aging may cause it to collapse slightly due to weakening of the dura). This increase in the venous pressure gradient is critical to brain blood and CSF flow in upright posture. It is also important to the passive production of CSF, brain flotation and support. Humans use emissary veins as well as the hypoglossal and condylar canals to connect the dural sinues of the brain to the VVP for drainage during upright posture.
RA is associated with spondylosis, stenosis, scoliosis and cervical syndromes, especially upper cervical syndromes, which can affect the neural canal and VVP. RA can thus affect the drainage system of the brain as well as CSF flow. In this regard, RA has been associated with NPH.