括約筋 かつやくきん Meanings Noun sphincter (muscle); constrictor Kanji 括 tie up. Read as カツ. 約 promise. Read as ヤク. 筋 muscle. Read as キン. Words containing 括約筋 肛門括約筋 (こうもんかつやくきん) anal sphincter 膀胱括約筋 (ぼうこうかつやくきん) sphincter muscle of urinary bladder 瞳孔括約筋 (どうこうかつやくきん) sphincter muscle of the pupil And 2 more. Word lists Anatomy Jinuma: Japanese Dictionary · Word lists