Foot Taiyang Bladder Meridian zú tài yáng páng guāng jīng · 足太阳膀胱经

Course. Starts at the inner corner of the eye, crosses the top of the head, runs down the back in two parallel lines, then the back of the leg to the little toe. 67 points on one side — the longest meridian.

Paired with. Bladder / Kidney 膀胱·肾

The two parallel back lines carry the Back-Shu points, which are named after the Zang-Fu systems and used to address them — which is why much of what is needled in a back treatment sits on this meridian.