Mulliken and Glowacki's seminal classification of vascular anomalies into vascular tumors (with infantile hemangiomas being paradigmatic) versus nontumorous vascular malformations has been as important in the head and neck region as elsewhere. These latter are congenital, have an equal gender incidence, virtually always grow in size with the patient during childhood, and virtually never involute spontaneously. The vascular malformations can in turn be subclassified into high-flow and low-flow. Our focus is on the low-flow malformations, which include those with venous, lymphatic, and, to a lesser extent, capillary components. We address diagnostic and clinical characteristics, particularly insofar as they relate to the structures of the head and neck, and discuss neurointerventional management in some detail.