What is the relationship between the clival venous plexus and the inferior petrosal sinus?

From the Guidelines

The clival venous plexus and inferior petrosal sinus are anatomically connected, with the clival venous plexus draining into the inferior petrosal sinus, which is a crucial pathway for venous outflow from the skull base. The inferior petrosal sinus is one of the sinuses that draining veins from the brain can reach, as noted in a study on reporting terminology for brain arteriovenous malformation clinical and radiographic features for use in clinical trials 1. This study highlights the importance of understanding the venous drainage system of the brain, including the role of the inferior petrosal sinus. Some key points about the relationship between the clival venous plexus and inferior petrosal sinus include:

• The clival venous plexus is a network of small veins located on the clivus, a sloping surface of the occipital bone at the skull base
• The inferior petrosal sinus runs along the petro-occipital fissure between the petrous portion of the temporal bone and the basilar part of the occipital bone
• The inferior petrosal sinus connects the cavernous sinus anteriorly to the jugular bulb posteriorly, where it joins the internal jugular vein
• This relationship is clinically significant because the clival venous plexus provides collateral venous drainage when the normal venous outflow is compromised. Understanding this anatomical connection is essential for neurosurgeons and interventional radiologists when planning procedures in this region, as damage to these venous structures can lead to significant bleeding.

From the Research

Relationship between Clival Venous Plexus and Inferior Petrosal Sinus

• The clival venous plexus is connected to the inferior petrosal sinus through emissary veins, as identified in 28.0% of cases in a study using computed tomography digital subtraction venography 2.
• The clival diploic vein (CDV) provides collateral channels between the cavernous sinus and the internal jugular vein, and the inferior petrosal sinus and the inferior petro-occipital vein (IPOV) 2.
• The inferior petroclival vein (IPV) drains into the caudal end of the inferior petrosal sinus in 96.1% of cases, as shown in a radiological analysis of 26 patients 3.
• The inferior petrosal sinus is an important component of the cerebral venous system, with implications in diagnosis and treatment of various diseases, and its anatomy is crucial for open surgical approaches to the skull base and endovascular access to the cavernous sinus and sellar region 4.
• The skull base venous channels, including the inferior petroclival vein, have multiple connections with surrounding venous structures and can occasionally obstruct the surgical view or be implicated in intraoperative hemorrhage, air embolism, or postoperative hematoma during endoscopic skull base surgery 5.
• Retrograde flow in the left inferior petrosal sinus can occur due to blood steal from the internal jugular vein toward the cavernous sinus because of venous stenosis in the brachiocephalic vein, as demonstrated in a study using MR angiography 6.