瞳孔括約筋 どうこうかつやくきん Meanings Noun sphincter muscle of the pupil; sphincter pupillae Kanji 瞳 pupil. Read as ドウ. 孔 aperture. Read as コウ. 括 tie up. Read as カツ. 約 promise. Read as ヤク. 筋 muscle. Read as キン. Word lists Anatomy Jinuma: Japanese Dictionary · Word lists