#LABELED INTERNAL AUDITORY CANAL MRI SERIES#

Roof – Formed by a membrane which separates the cochlear duct from the scala vestibuli, known as the Reissner’s membrane.Lateral wall – Formed by thickened periosteum, known as the spiral ligament.The cochlear duct can be described as having a triangular shape: The presence of the duct creates two canals above and below it – the scala vestibuli and scala tympani respectively. It is held in place by the spiral lamina.

The cochlear duct is located within the bony scaffolding of the cochlea. The semi-circular ducts, saccule and utricle are the organs of balance (also known as the vestibular apparatus). The cochlear duct is situated within the cochlea and is the organ of hearing. It is composed of the cochlear duct, three semi-circular ducts, saccule and the utricle. It lies within the bony labyrinth, surrounded by perilymph. The membranous labyrinth is a continuous system of ducts filled with endolymph. They have a swelling at one end, known as the ampulla.įig 2 – The three parts of the bony labyrinth. The canals are situated superoposterior to the vestibule, at right angles to each other. They contain the semi-circular ducts, which are responsible for balance (along with the utricle and saccule). There are three semi-circular canals: anterior, lateral and posterior.

Scala tympani: Located inferiorly to the cochlear duct.

As its name suggests, it is continuous with the vestibule.

Scala vestibuli: Located superiorly to the cochlear duct.

The presence of the cochlear duct creates two perilymph-filled chambers above and below: Branches from the cochlear portion of the vestibulocochlear (VIII) nerve are found at the base of the modiolus.Įxtending outwards from the modiolus is a ledge of bone known as spiral lamina, which attaches to the cochlear duct, holding it in position. It twists upon itself around a central portion of bone called the modiolus, producing a cone shape which points in an anterolateral direction. The cochlea houses the cochlea duct of the membranous labyrinth – the auditory part of the inner ear. Two parts of the membranous labyrinth the saccule and utricle, are located within the vestibule. It is separated from the middle ear by the oval window, and communicates anteriorly with the cochlea and posteriorly with the semi-circular canals. The vestibule is the central part of the bony labyrinth. It consists of three parts – the cochlea, vestibule and the three semi-circular canals.

#LABELED INTERNAL AUDITORY CANAL MRI SERIES#

The bony labyrinth is a series of bony cavities within the petrous part of the temporal bone. The oval window lies between the middle ear and the vestibule, whilst the round window separates the middle ear from the scala tympani (part of the cochlear duct). The inner ear has two openings into the middle ear, both covered by membranes. The membranous labyrinth is filled with fluid called endolymph. It consists of the cochlear duct, semi-circular ducts, utricle and the saccule. Membranous labyrinth – lies within the bony labyrinth.All these structures are lined internally with periosteum and contain a fluid called perilymph. It is composed of the cochlea, vestibule and three semi-circular canals. Bony labyrinth – consists of a series of bony cavities within the petrous part of the temporal bone.The inner ear has two main components – the bony labyrinth and membranous labyrinth. It lies between the middle ear and the internal acoustic meatus, which lie laterally and medially respectively. The inner ear is located within the petrous part of the temporal bone.

Labeled internal auditory canal mri