The paravestibular canaliculus was studied by light microscopy in serial sections of the temporal bones from otosclerotic patients who underwent fenestration or stapes surgery. In all examined 23 specimens (13 cases), the endolymphatic duct and sac were observed to be normally developed with no pathological findings. The paravestibular canaliculus was found in 14 of the specimens (60.9%). Its course was traced from the proximal to the distal area in 12 specimens, and it appeared to merge into the distal portion of the endolymphatic sac in 7 of them. Twelve of the paravestibular canaliculi contained one vein, and 3 contained several veins. No artery was found. The paravestibular canaliculus was observed to originate from small vascular channels around the vestibule in the otic capsule, lateral to and near the internal aperture of the vestibular aqueduct.</p
