Glossary
Angiogram
Description
a special test that is performed by an experienced radiologist where a plastic tube or catheter is inserted into one of the blood vessels in the groin and is then advanced to the blood vessels in the neck. Using this test, multiple tumors can be identified and arterial blood vessels feeding the tumor can be clotted off.
Auditory brainstem response
Description
a special hearing test done while a patient is hearing clicks or certain tones.
Canal wall down procedure
Description
a procedure where the bony partition between the back part of the ear canal and mastoid is removed
Canal wall up procedure
Description
a procedure where the bony partition between the back part of the ear canal and mastoid is kept intact
Cerebellum
Description
portion of the brain found in the posterior fossa which regulates fine motor coordination
Chorda tympani nerve
Description
a nerve which transmits taste information from the front two-thirds of the tongue back to the brain. The nerve travels through the middle ear close to the ossicles.
Conductive Loss
Description
A type of hearing loss which arises from the middle ear, due to wax, fixation of the ossicles, ear infection etc., and is often easily corrected by medication and/ or surgery.
Congenital cholesteatoma
Description
a cholesteatoma that arises in an ear from squamous epithelium that became entrapped within the middle ear or petrous apex
CT scan
Description
a computerized tomography scan or special X-ray which allows more detailed views of bony structures and soft tissue
Electronystagmogram (ENG)
Description
a balance test which involves recording movements of the eyes while changing positions of the head with respect to the earth's gravitational field. The eye movements are also recorded while cool and warm air is blown into the ear canal.
Embolization
Description
a procedure done during angiography which involves blocking the blood vessels supplying blood to the tumor
Internal auditory canal
Description
a bony canal which contains the cochlear, vestibular, and facial nerves
Internal Jugular Vein
Description
a vein that collects blood from the brain and empties eventually into the heart
Jugular bulb
Description
a venous cavity which receives blood from the sigmoid sinus and empties into the internal jugular vein
Mastoid
Description
the bone located directly behind the external ear which communicates with the middle ear
Mastoidectomy
Description
a procedure to remove part of the mastoid in order to clean out infection and remove cholesteatoma
Middle Fossa approach
Description
a hearing preservation approach which allows visualization of the roof of the internal auditory canal for removal of small tumors. This approach involves a craniotomy above the ear.
Mixed Loss
Description
A type of hearing loss caused by a problem with both the middle and inner ear/nerve simultaneously.
Modified radical mastoidectomy
Description
a procedure where the bony partition between the back part of the ear canal and mastoid is removed and an ossicular reconstruction with repair of the eardrum is also performed
Myelin
Description
a substance which insulates nerves and allows for more efficient transmission of electrical signals
Ossicular reconstruction
Description
a procedure to repair the ossicles so that sound transmission can occur to the inner ear
Otolith organs
Description
balance organs responsible for detecting linear acceleration of the head. These include the utricle and the saccule.
Paraganglia
Description
cells located around the middle ear, jugular bulb, or carotid artery in the neck which are thought to detect oxygen and carbon dioxide levels in the bloodstream
Petrous apex epidermoid
Description
a cholesteatoma that arises from squamous epithelium that became entrapped within the petrous apex
Radical mastoidectomy
Description
a procedure done where the eardrum, malleus, and incus are removed and the bony partition between the back part of the ear canal and mastoid is also removed.
Saccule
Description
part of the inner ear responsible for gathering information relating to linear acceleration of the head
Schwann cells
Description
type of cell which coats the peripheral segment of nerves and produces a substance called myelin
Semicircular canals
Description
part of the inner ear involved in gathering information on head motion
Sensorineural Loss
Description
A type of hearing loss arising from the inner ear and/or nerve, which in most cases is permanent, due to aging, ototoxic drugs, noise exposure, etc. Hearing aids are the best remedy for a sensorineural loss.
Sigmoid sinus
Description
a large vein found deep within the mastoid which collects blood from the brain and empties into the jugular bulb
Suboccipital approach
Description
a hearing preservation approach which involves a craniotomy far behind the ear that allows visualization of the posterior portion of the internal auditory canal.
Translabyrinthine approach
Description
an approach which involves an incision behind the ear and a craniectomy through the semicircular canals of the inner ear. This allows visualization of the posterior aspect of the internal auditory canal. Hearing is always lost.
Utricle
Description
part of the inner ear responsible for gathering information relating to linear acceleration of the head
Vein
Description
a vessel that carries blood away from other organs and to the heart. The red blood cells within veins have a lower oxygen content.