Brain Door

Naohu, 脑户, is the “door of the brain.” 脑 (腦) is the brain; 户 (戶), the door. The point lies over the occipital protuberance, and the name presents it as the entrance of the Du Mai to the brain.

Its most famous mention is in the Suwen (Basic Questions), in the chapter Ci Jin Lun (刺禁論), devoted to the prohibitions of needling: «刺頭，中腦戶，入腦立死»: when needling the head, if Naohu is struck and the needle enters the brain, death is immediate. The Zhenjiu Jiayi Jing (Systematic Classic of Acupuncture and Moxibustion) records the phrase and also includes it in its list of points where moxa is not applied, along with other cranial points of the Du Mai.

Reference works attribute a long list of alternative names to it: 匝風, 會額, 合顱, 仰風, 會顱, and 迎風. The explanations given for each are modern interpretations. The Zhenjiu Jiayi Jing uses it as a reference to locate BL9, Yuzhen, beside it.