The Tegmento-Vermian angle is an important measurable parameter in assessment of the posterior fossa abnormalities. The angle is constructed on sagittal midline images (MRI) of the fetal brain.
Tegmento-vermian angle is the angle formed by1:
Line1- along the dorsal surface of the brain stem parallel to the tegmentum and which should transect the nucleus gracilis at the obex.
Line 2- along the ventral surface of the vermis.
Normally the angle is close to 0 degree and elevated angle is often associated with posterior fossa malformations1,2.