Glossary

Acoustic neuroma

Description

vestibular schwannoma

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.

Artery

Description

a vessel which carries richly oxygenated blood from the heart to other organs

Audiogram

Description

a hearing test conducted in a sound-proof room by a qualified audiologist 

Auditory brainstem response

Description

a special hearing test done while a patient is hearing clicks or certain tones. 

Bilateral

Description

on both sides 

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 

Central

Description

near the brainstem 

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. 

Cochlea

Description

part of the inner ear involved in hearing

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 

Conjunctiva

Description

the white part of the eye 

Craniectomy

Description

permanent removal of a portion of the skull over the brain. 

Craniotomy

Description

temporary removal of a portion of the skull over the brain. 

CT scan

Description

a computerized tomography scan or special X-ray which allows more detailed views of bony structures and soft tissue

Dura

Description

a tough fibrous layer found immediately under the skull that protects the brain. 

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 

Endolymph

Description

one of two different fluids found in the inner ear 

Endolymphatic hydrops

Description

a condition of excessive fluid within the endolymphatic space 

Glomus Jugulare

Description

a paraganglioma which arises from paraganglia around the jugular bulb 

Glomus tympanicum

Description

a paraganglioma which arises from paraganglia in the middle ear 

Hydrocephalus

Description

a buildup of spinal fluid that can lead to brain dysfunction and death 

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

Keratin

Description

a protein found in cells that form squamous epithelium 

Lacrimal glands

Description

glands that produce tears in the eyes 

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 

Meniere's disease

Description

endolymphatic hydrops for which no cause can be identified 

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 

Obersteiner-Redlich zone

Description

area where schwann cells meet oligodendroglia cells 

Oligodendroglia cells

Description

type of cell which coats the central segment of nerves

Ossicles

Description

the three bones behind the eardrum, namely the malleus, incus and stapes 

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. 

Otoliths

Description

small stones found in the otolith organs 

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

Perilymph

Description

another type of fluid found in the inner ear 

Peripheral

Description

near the inner ear

Petrous apex

Description

bone that is located deep to the inner ear

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

Squamous epithelium

Description

skin

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.

Tinnitus

Description

ringing or noise in the ears

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.

Trigeminal nerve

Description

the nerve which transmits information on facial sensation, not motion

Tympanic membrane

Description

eardrum

Tympanoplasty

Description

a procedure to repair the eardrum and the ossicles

Unilateral

Description

on one side

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.

Vertigo

Description

a sensation of surrounding objects spinning around you or a sensation that you are being spun around

Vestibular

Description

pertaining to the function of balance

Vestibular schwannoma

Description

acoustic neuroma

About Dr. Prasad

Dr. Sanjay Prasad MD FACS is a board certified physician and surgeon with over thirty-two years of sub-specialty experience in Otology, Neurotology, advanced head and neck oncologic surgery, and cranial base surgery. He is chief surgeon and founder of the private practice, Metropolitan NeuroEar Group, located in the metropolitan Washington D.C. area.