Also Bend-Center welling-abscess. A welling-abscess (yōng) located at BL-40 (Bend Center, 委中 wěi zhōng), i.e., on the back of the knee (popliteal fossa). A Bend-Center toxin is attributed to accumulated heat in the gallbladder channel binding in the bladder channel or to stagnation of qì and blood in the kidney channel. Sometimes it develops from other sores at the site. The back of the knee becomes as hard as stone, is slightly red and swollen or scorching hot and red with generalized heat and aversion to cold. It makes bending and stretching difficult and causes flexing. When the pain and swelling grow more severe day by day and the heat effusion and aversion to cold do not abated, this is a sign that pus has formed.
Medicinal therapy: Quicken the blood and transform stasis. Use Blood-Quickening Stasis-Dispersing Decoction (活血散瘀汤huó xuè sàn yū tāng).