sphincter muscle of the pupil; sphincter pupillae
pupil (of eye)
ドウ / ひとみ
cavity, hole, slit, very, great, exceedingly
コウ / あな
fasten, tie up, arrest, constrict
カツ / くく.る
promise, approximately, shrink
ヤク / つづ.まる
muscle, sinew, tendon, fiber, plot, plan, descent
キン / すじ