Foramen lacerum and pterygosphenoidal fissure, basal view. The pterygosphenoidal fissure runs between the pterygoid process and the sphenoid rostrum, and represents a key surgical landmark to identify the lower aspect of the foramen lacerum. The vidian canal and the pterygosphenoidal fissure converge at an approximate 45 degree angle at the level of the foramen lacerum. The lacerum process of the medial pterygoid plate has a triangular shape with its vertex pointing toward the foramen lacerum. This triangular prominence located between vidian canal and lacerum process can also been called the pterygoid tubercle. The vaginal process articulates in front with the sphenoidal process of the palatine and behind this with the ala of the vomer. (Image courtesy of JC Fernandez-Miranda)