[Location] Localized in the supine position, and genuflex, on perineal region, at the middle point between Huiyin ( RN1 ) and anus. (Fig.98)
 
[Regional Anatomy] Skin→subcutaneous tissue→centrnm tendineum permea. Superficial layer, the distribution of rami perineales nervi cutanei femoris posterioris, the branch of perineal nerves from pudendal nerve; deep layer, the branch of pudendal nerve, the branches or the subordiantial ramus of internal pudendal artery and vein.