Abstract:A singular mastoid emissary vein is a small venous channel without a valve. It is connected to the sigmoid sinus with either the posterior auricular or the occipital veins. The morphology and shape of the mastoid emissary veins are different in different individuals. Pulsatile tinnitus caused by abnormally enlarged mastoid veins is a research hotspot in the field of otology in recent years. Its incidence is increasing year by year. Meanwhile, with the rapid development of microsurgery, there are more and more surgeries involving the mastoid region. Accidental bleeding and embolization often occur due to unintentional injury to the mastoid emissary vein during surgery. Therefore, it is necessary to reveal the true nature of the mastoid emissary veins. This paper discusses the origin, anatomy, clinical significance and so on of the mastoid emissary veins.