The Bladder channel is the longest in the system and carries the most points, sixty seven of them, running from the inner corner of the eye over the crown, down the back in two parallel lines, and along the back of the leg to the little toe. Its length is out of all proportion to the organ it is named for, and the tradition's use of it is correspondingly wide.
The reason is the row of back shu points, the transport points, which lie along the inner branch of the channel on either side of the spine. Each of the twelve organs of the system has one, arranged from the top down in roughly the order the organs sit in the trunk: Lung high between the shoulder blades, Kidney low in the lumbar region. This makes the Bladder channel a kind of index of the whole scheme, and it is the reason a practitioner working in this tradition may attend to the back when the named concern is elsewhere.
The outer branch of the channel carries a second row, named for the spirits the tradition associates with each organ, and those names are among the most poetic in the classical literature.
The Bladder pairs with the Kidney as the yang and yin of Water and holds the horary period from three to five in the afternoon.
The atlas records the tradition's arrangement and makes no anatomical or clinical claim about it.