Webster's New World Medical Dictionary

dyspraxia
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E. coli
Escherichia coli, a bacterium that nor-
mally resides in the colon. Although E. coli is nor-
mally present in the colon with no harmful
consequences, it can cause disease when transmit-
ted from human to human via water, food, or feces.
Infants, young children, the elderly, and people with
compromised immune systems are especially at risk
for E. coli infection.
Eagle syndrome
Inflammation of the styloid
process, a spike-like growth that projects out of the
base of the skull. If the styloid process is oversized
or projects too far, the tissues in the throat can rub
on it causing pain during the act of swallowing and
pain on rotation of the neck. Diagnosis of Eagle syn-
drome is made by an X-ray demonstrating an abnor-
mally elongated styloid process.
ear
The hearing organ. There are three sections
of the ear: outer, middle, and inner. The outer, or
external, ear helps concentrate the vibrations of air
created by sound onto the eardrum, causing the
eardrum to vibrate. These vibrations are transmitted
by a chain of little bones in the middle ear to the
inner ear, where they stimulate the fibers of the
auditory nerve to transmit impulses to the brain.
The auditory cortex of the brain interprets speech
and other sounds that the ear receives as informa-
tion we can use to interpret our environment. See
also 
ear, inner; ear, middle; ear, outer.
ear, cauliflower
See 
cauliflower ear.
ear, external
See 
ear, outer.
ear, inner
A highly complex structure whose
essential component for hearing is the membranous
labyrinth, where the fibers of the auditory nerve
connect the ear to the brain. The membranous
labyrinth is a system of communicating sacs and
ducts (tubes) filled with fluid (endolymph), and it is
lodged within a cavity called the bony labyrinth. At
some points the membranous labyrinth is attached
to the bony labyrinth, and at other points the mem-
branous labyrinth is suspended within the bony
labyrinth in a fluid called perilymph. The bony
labyrinth has three parts: a central cavity called the
vestibule; semicircular canals, which open into the
vestibule; and a spiraling tube called the cochlea.
The membranous labyrinth also has a vestibule,
which consists of two sacs (the utriculus and saccu-
lus) that are connected by a narrow tube. The larger
of the two sacs, the utriculus, is the principal organ
of the vestibular system, which is the system of bal-
ance. This system informs a person about the posi-
tion and movement of the head. The smaller of the
two sacs, the sacculus, is also connected by a mem-
branous tube to the cochlea that contains the organ
of Corti. The hair cells, which are the special sen-
sory receptors for hearing, are in the organ of Corti.