Medial to the opening for the

carotid canal The carotid canal is a passage in the petrous part of the temporal bone of the skull through which the internal carotid artery and its internal carotid (nervous) plexus pass from the neck into (the middle cranial fossa of) the cranial cavity. ...

and close to its posterior border, in front of the

jugular fossa The jugular fossa is a deep depression ( fossa) in the inferior part of the temporal bone at the base of the skull. It lodges the bulb of the internal jugular vein. Structure The jugular fossa is located in the temporal bone, posterior to the ...

, is a triangular depression; at the apex of this is a small opening, the aquaeductus cochleae (or cochlear aqueduct, or aqueduct of cochlea), which lodges a tubular prolongation of the dura mater establishing a communication between the

perilymphatic space Perilymph is an extracellular fluid located within the inner ear. It is found within the scala tympani and scala vestibuli of the cochlea. The ionic composition of perilymph is comparable to that of plasma and cerebrospinal fluid. The major cati ...

and the subarachnoid space, and transmits a vein from the

cochlea The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus (cochlea), modiolus. A core component of the cochlea is the organ of Cort ...

to join the internal jugular vein. The cochlear aqueduct lies perpendicular to the petrous apex, in contrast with the

vestibular aqueduct At the posterior lateral wall of the temporal bone is the vestibular aqueduct, which extends to the posterior surface of the petrous portion of the temporal bone. The vestibular aqueduct parallels the petrous apex, in contrast to the cochlear ...

, which lies parallel to the petrous apex.

Additional images

File:Gray187.png, Base of skull. Inferior surface.

References

Bones of the head and neck {{musculoskeletal-stub