Cochlear canaliculus

The cochlear canaliculus, also known as the aqueduct of the cochlea, is a slender bony channel that  originates from the scala tympani in the bony cochlea, near its basal turn. It opens into a triangular depression located anteromedially to the jugular fossa. This triangular indentation extends mostly within the petrosal area but also reaches back into the posterior cranial fossa. The apex of this indentation is where the canaliculus leads into. Inside the cochlear canaliculus is the perilymphatic duct, which is an epithelial-lined pathway that may be an extension of the dura mater from the inner ear. This duct drains perilymph into the cerebrospinal fluid located in the subarachnoid space of the cranial cavity, specifically in the posterior cranial fossa. The communication between the perilymph in the cochlea and the cerebrospinal fluid in the subarachnoid space through this channel is essential for regulating and maintaining the fluid pressure within the inner ear.