The etiological basis of trigeminal neuralgia (TN) is unknown but vascular (arterial and venous) compression of the trigeminal nerve roots has emerged as the likely cause in most cases. Here we examine the evidence for the “brain sagging/arterial elongation hypothesis” with reference to the cerebral arteries and veins believed to cause the compression. Most often implicated are the superior cerebellar artery, the anterior and posterior inferior cerebellar arteries, and the superior petrosal vein including several of its tributaries. The reviewed data suggest that the theoretical support for a vascular compressive etiology of TN is weak, albeit the surgical outcome data are relatively convincing. Clin. Anat. 27:89–93, 2014. © 2013 Wiley Periodicals, Inc.