括約筋 (Koat-iok-kin) (括約筋) 是 (sī)動物 (tōng-bu̍t)體內 (thé-lāi)的 (ê)這款 (chit-khoán)權橫 (khoân-hêng)筋肉 (kin-bah)。括約筋主要 (chú-iàu)分佈 (hūn-pò͘)佇 (tī)人 (lâng)的尻川口 (kha-chhng-kháu),尿道 (jiō-tō),膀胱 (phông-kong)佮 (kap)為 (ūi)的噴們 (phùn-bûn)和 (hām)幽門 (iu-bûn)。