Perineum vessel is collateral that distributed over perineum area and pertains to branch of governor vessel. Governor vessel is at taiyang vessel of anus and ascends through spine then pertains to kidney. Bladder meridian joins kidney along bilateral sides of spine. Perineum vessel will cause diseases of lumbago, dripping great sweat and dry with liking for fluids and appear engorged blood vessels at distribution areas of bladder meridian of lower limps which is 5 cun below ham. It will be hemorrhage when acupuncture.

There is record in original context that perineum vessel starts from which vessel. Its treatment position is bladder meridian. Analysis from the name, bladder meridian is not perineum vessel, because ancient people could not lump yin and yang together. Wang bing thinks bladder meridian is part of taiyang meridians, because taiyang vessels run downward and pass posterior aspect of perineum to cleft. Its note is correct. Vessels that distributed over perineum are recorded in twelve meridians, twelve divergent collaterals, and fifteen collaterals of Lingshu. They include governor vessel, conception vessel, thoroughfare vessel, and liver meridian, collateral of liver meridian, gallbladder meridian, divergent collateral of gallbladder meridian and divergent collateral of bladder meridian. Only divergent collateral of bladder meridian descends from perineum and passes dorsal side of lower limps. After bladder meridian is distributed over perineum, its divergent collateral diverges from ham and runs upward then enters into anus. From here Taiyang meridian connects with collateral which is distributed over perineum.

Perineum vessel is collateral of governor vessel which is distributed over perineal region. Governor vessel links with bladder meridian and bladder meridian descends along posterior aspect of thigh to 5 cun below ham. So perineum vessel can cause lumbago and the symptom can be treated on bladder meridian (Zhiyang is medial line of taiyang).