Anterior pontomesencephalic vein

The anterior pontomesencephalic vein (APMV) is a longitudinal vein running along the anterior surface of the pons and mesencephalon and in the interpeduncular fossa. Uncommonly it can become large and can potentially lead to confusion on imaging. In a midline position, it is called the median anterior or anteromedian pontomesencephalic vein. In a more lateral position, it is called the lateral anterior pontomesencephalic vein.

Gross anatomy

The anterior pontomesencephalic vein runsanterior to the pons and mesencephalon and adheres to the anterior surface of those structures ¹. It drains blood from the small pontine and mesencephalic veins into the basal veins of Rosenthal via the peduncular veins ^1-3. It might be directly continuous towith the anterior medullary vein or connect to it via one or both transverse pontine veins ^1,2. Furthermore, it might connect to the superior petrosal vein/petrosal sinus, cavernous or marginal sinus via bridging veins ^2,3.

Radiographic features

CT

The anterior pontomesencephalic vein is visible in up to 4% of CT angiograms and in about half of the cases, it can become large enough to be confused with an arterial structure ¹.  If large it can also cause hyperattenuation in the interpeduncular cistern on non-contrast CT ¹.

Clinical importance

Dural arteriovenous fistulas can drain through bridging veins as the transverse pontine veins into pontomesencephalic venous system ².

The mesencephalic veins might become obstructed as a result of transtentorial herniation or surgical procedures with subsequent haemorrhage ³.