“Yin” means something thick and deep or located centrally, but it also refers to large size or the red colour. “Men” means gate. The point is located in the posterior aspect of the thigh, where the muscles are abundant and thick, and is indicated in lumbar sprain and lumbago due to the coagulation of evil blood. Hence, the name Yinmen (Thick Red Gate).
The line joining the midpoint of the transverse gluteal fold and the midpoint of the transverse crease of the popliteal fossa is about 14 cun long. The point is located on this line 6 cun below the transverse gluteal.
Lumbago (with Kunlun (BL60) and Dachangshu (BL25)).
Numbness of the lower extremities.
Relax the tendons.