Abducens Nucleus
The motor nucleus of the abducens nerve, located in the caudal pons. It contains not only the motor neurons for the ipsilateral lateral rectus, but also a collection of interneurons whose axons cross the midline immediately and ascend to contralateral medial rectus motor neurons through the MLF.
Acoustic Nerve
The nerve that carries impulses concerned with balance and hearing between the inner ear and the brain.
Acoustic Neuroma
A tumor growing from the acoustic nerve.
Afferent
Afferent is a general term applied to nerves or blood vessels that means nerve signals or blood are traveling from the peripheral to the center of the body.
Ampulia
The ampulla is the enlarged portion of each semicircular canal that possesses the sensory area of the semicircular canal.
BPPV
Vestibular disorder that causes dizziness, vertigo, and imbalance, usually when the head is moved in a particular direction.
Brainstem
The central area of your brain which receives information relating to balance and initiates muscle adjustments which enable you to keep your balance and to maintain clear vision as you move.
Cerebellum
The muscle coordination center of your brain.
Cerebral Cortex
The part of your brain that controls voluntary movements and coordinates thinking and memory.
Cholesteatoma
A cyst-like growth that occurs most commonly in the middle ear.
Cochlea
The part of your inner ear that contains the organ of hearing.
Cupula
A gelatinous material that covers the hair cells within each of the semicircular canals.
Endolymph
A fluid contained within the semicircular canals, the vestibule, and the cochlea of the inner ear.
Endolymphatic Hydrops
A vestibular disorder that causes dizziness, vertigo, and/or imbalance when there is a fluctuation in pressure or composition of the endolymph.
Hair Cells
The sensory receptors of the vestibular system; located in the macular organs and the cupula of each semicircular canal.
Hydrops
Refer to endolymphatic hydrops.
Idiopathic
A condition which occurrs without known cause.
Labyrinth
Inner ear.
Labyrinthitis
Inflammation of the inner ear.
Macula
A patch of hair cells in either the saccule or utricle; covered with gelatinous material containing otoliths.
Meniere's Disease
A vestibular disorder of unknown cause which occurs at intervals and is characterized by vertigo, tinnitus, a feeling of fullness in the ear, and fluctuating hearing loss.
Nystagmus
Involuntary, coordinated eye movement which occurs as your head moves or as your eyes follow a moving object.
Otic Capsule
The bone surrounding the inner ear.
Otoliths
Small granules of calcium carbonate; found in the macula of the utricle and saccule.
Ototoxic
Its the "poisonous to the ear;" a substance that affects hearing or vestibular functions.
Oval Window
A thin walled tissue that covers one of the two openings between the middle ear space and the fluid-filled inner ear.
Perilymph Fistula
A vestibular disorder caused by an abnormal opening between the middle ear space and the fluid-filled inner ear; results in symptoms of dizziness, vertigo, imbalance, and/or hearing loss.
Proprioceptors
The specialized nerve endings located in muscles and around joints which are sensitive to touch, pressure, and movement of the muscle tissue surrounding them.
Round Window
Thin-walled tissue that covers one of the two openings between the middle ear space and the fluid-filled middle ear.
Saccule
A part of the vestibular system containing sensory receptors that are sensitive to changes in head motion with respect to earth vertical.
Semicircular Canals
The part of the vestibular system which contains nerve endings that are sensitive to changes in head movement in any direction.
Tinnitus
A ringing or noise in the ear.
Uticle
Part of the vestibular system containing sensory receptors that are sensitive to changes in head motion with respect to earth horizontal.
Vertigo
The sensation of rotation or movement of yourself or your surroundings.
Vestibular Nerve
The nerve which carries impulses concerning balance between the inner ear and the brain; a branch of the acoustic nerve.
Vestibular System
The portion of the inner ear concerned with balance and body orientation; consists of semicircular canals and vestibule.
Vestibule
Part of the vestibular system which contains nerve endings that are sensitive to changes in head movement with respect to gravity.