The microfissure between the round window niche and the posterior ampulla.
D000328:Adult; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D007758:Ear, Inner / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D011247:Pregnancy; D012665:Semicircular Canals / Q000033:anatomy & histology*