Isolated dissection of the posterior cerebral artery (PCA) is a rare but important cause of stroke in younger patients, particularly women. We present 3 cases of dissection of the P2 segment of the PCA. In 2 patients, an association with minor axial head trauma was documented, suggesting shearing injury of the PCA as it crosses over the free edge of the tentorium. The clinical and imaging findings are discussed, and the therapeutic management is reviewed.