Inferior petrosal sinus

Looks like

A narrow channel along the lower edge of the petrous temporal bone, running from the cavernous sinus to the jugular vein.

What it does

Drains the cavernous sinus and part of the brainstem into the internal jugular vein.

Keeping it well

Blood samples taken from here with a fine catheter show whether a pituitary tumour is making too much ACTH in Cushing's disease.

Its parts

• Basilar venous plexus
• Cavernous sinus

Related conditions

• Chronic venous insufficiency
• Clotting disorders (thrombophilia & APS)
• Deep vein thrombosis
• Varicose veins