ANATOMY and
PHYSIOLOGY of ENTORGANS
Dr. Mohammed Al-Tuwaijry
Senior Consultant and Head
Department of
Otorhinolaryngology.
The ear
The ear is divided into
three large parts:
 The external ear
 The middle ear
 The inner ear
The outer ear
The outer ear comprises the pinna and the
external auditory rneatus. The outer part
of this is cartilaginous. The deep part is
bony.
The cartilaginous meatus contains hair
follicles and glands which secrete wax.
The hair follicles extend only for a short
distance into the ear and are not found in
the deeper parts of the external meatus.
The external meatus varies in size and
form with growth.
The topography of meatus:
The middle cranial fossa is above.
The mastoid bone is behind.
The joint of the lower jaw is in front
The parotid gland is below
The Middle Ear

The
tympanum
 The
Eustachian
tube
 The mastoid
antrum and
cells
The tympanic membrane
The tympanic membrane consists of
three layers — an outer epithelial
layer, a middle layer of yellow
elastic fibrous tissue and an inner
layer of mucous.
The drum membrane is divided into two
parts, the pars tensa (1) and the
pars flaccida (2). In the pars
flaccida the fibrous layer is
absent. This area constitutes only
the small uppermost part of the
eardrum and is sometimes difficult
to see. It is frequently referred to
as the attic part of the eardrum;
chronic perforations in this area
are potentially dangerous, as will
be seen later.
The Landmarks of the Eardrum
The most prominent landmark is the handle
of the malleus, seen as a white streak
running down to the approximate
centre of the drum. At its upper end is
a small projection known as the short
process.
In the drum membrane are two folds
stretching anteriorly and posteriorly
from the short process. They are
known as the anterior and posterior
mallear folds and the part of the drum
above this level constitutes the pars
flaccida.
1.
The umbilicus of eardrum
2.
The Handle of the malleus
3.
The posterior fold
4.
The short process of the malleus
5.
The anterior fold
6.
The light reflex.
The Tympanum

The middle ear can be divided
into three portions. The
uppermost portion is the attic,
the middle portion the
mesotympanum, and the
lowest portion the
hypotympanum. The attic is
that part
of the middle ear above the
level of the mallear folds. It is
divided into a number of small
pockets by the contained
ossicles, their ligaments and
mucosal folds. Chronic infection
may localize in these spaces. It
should be noted that the middle
ear extends beyond the limits of
the drum.
The Ossicles of the Middle Ear
The middle ear is an aircontaining space and
contains three ossicles:
the malleus, incus and
stapes.
The handle of the malleus is
firmly embedded in the
middle layer of the drum.
The stapes footplate
occupies the oval window
of inner ear




The malleus
The incus
The stapes
The eardrum
The Topography of
Tympanum
The middle cranial fossa – is
above
The mastoid bone (the biggest
cell is known as antrum or
cave) – is behind
The inner carotid - is in front of
The jugular vein – is below
The eardrum – is the lateral wall
The medial wall is the wall of the
inner ear with two windows:
oval window (connects with
the stapes) and round
window (closed by the
membrane of scala tympany)
The Eustachian tube
The Eustachian tube connects the
tympanum
and
the
nasopharynx. It is closed in
adults
and
opened
by
swallowing.
Functions:

Barometric (to maintain the
pressure of air inside the middle
ear
and
mastoid
system
approximately equal to the
external atmospheric pressure)

To drain the secret from the
middle ear to the nasopharynx

To protect the middle ear from
nasopharyngeal infection (due
to respiratory epithelium)
The characteristic of the Eustachian
tube in children

1. The Eustachian tube
is short, straight and
wide. It opens in
nasopharynx
much
below in compare with
adults.
 2. The Eustachian tube is
open all time.
 3.
The
respiratory
epithelium covered the
tube is underdeveloped in
newborn.
The characteristic of the middle ear
in newborn
 1.
There are remainders of
the embryonic mixoid tissue in
tympanum until 3 years old.
 2. There is no full ossification
of the tympanum walls. So that
there are places of contact
between mucous membrane of
middle ear and dura mater of
the brain.
The characteristic of the middle ear
in newborn
 The eardrum is more
thick than the eardrum
in adult. And the angle
between the eardrum
and the meatus is more
sharp so it is much
more difficult to look
carefully the babies
eardrum.
 1 – eardrum in adult
 2 – eardrum in newborn
The characteristic of the mastoid
bone in newborn
 There is only one air
cell of the mastoid
bone in newborn –
antrum or the cave.
So a newborn can’t
suffer from
mastoiditis but
antritis is a frequent
pathology of this
age.
NOSE and PARANASAL SINUSES
The external nose
The external nose is supported
by bone and cartilage.
The bony part is formed mainly
by the nasal bones on each
side, and the frontal process
of the maxillary bone.
The cartilaginous portion is
formed by several cartilages
which support and give
shape to the lower part of the
nose and nasal tip.
The nasal cavity
The nasal cavity is divided
by the nasal septum
into two parts which
have similar anatomical
structure but may be
asymmetrical
The septum of nasal cavity
The septum is a structure
composed partly of
cartilage and partly of a
bone.
The septum is covered by
perichondrium where
there is a cartilage, with
periosteum where there
is a bone, and outside
this with mucous
membrane.
Septum of nasal cavity
Nasal septum
deviation is the
frequent reason of
nasal obstruction.
Septum of nasal cavity
The lower and anterior
area of nasal septum is
known as Epistaxis
zone or Kisselbach
zone. This area from
which bleeding
commonly occurs in
patients due to
situation of arteries.
area,
The Lateral Wall of Nasal Cavity
On the lateral wall there is a
system of ridges known as
turbinates, each of which
overhangs a groove known
as a meatus:
1 – inferior
2 – middle
3 – superior
The inferior turbinates forms a
bone by itself, the others are
the parts of ethmoid bone.
Underlying the mucous
membrane there is erectile
tissue with many venous
blood vessels.
The Meatuses of the Nose
The meatuses of the nose
are of importance, since
they are the drainage
channels of the air
sinuses. The
appearance of pus in
one of the meatuses is
of diagnostic
importance in infections
of the air sinuses
opening into particular
meatus.
The Meatuses of the Nose
1 – inferior nasal
meatus
2 – common nasal
meatus
3 – middle nasal
meatus
4 – nasal septum
5 – middle turbinate
6 – inferior turbinate
The Nasal Functions
 1. Olfaction.
 2. Filtration.
 3.
Humidification and
warming of the air passing
to the lung.
 4. Vocal resonance.
 Aesthetic function.
The Nasal Functions
The functions depend upon the
mucous membrane with its
underlying tissues. In certain
areas such as the turbinates
this is a complicated structure of
ciliary
mucous
membrane,
glands, blood spaces and
connective tissues based upon
bone, and is under the control of
the autonomic nervous system.
In this way the turbinates act as
a valve mechanism, enlarging
or narrowing the air channels
and so determining the direction
of the air stream
Ciliary Action
Ciliary action is the means by which
the mucous membrane
cleanses itself and removes
unwanted material. By the
movement of the cilia a constant
streaming of mucus is produced
from the nostrils to the pharynx.
Any interference with normal
action causes unpleasant
symptoms. Post-nasal 'drip', or
'catarrh', which is so often a
cause of complaint, is an
expression of the inability of the
ciliary mechanism to deal with
thickened mucus, which slowly
finds its way into the pharynx,
where it accumulates. The
conditions necessary for
efficient ciliary action are mucus
of the correct consistency and
adequate aeration.
Filtration and Humidification


Filtration is effected by the
adhesion to the mucous film of dust,
bacteria and other particles. These
are removed by ciliary action into
the pharynx and swallowed with the
secretions.
Humidification. The moistening
and warming of the air passing to
the lungs is one of the chief
functions. Air reaches the lungs at
about 30°C and at 75-95% relative
humidity. When, during cold
weather, the air in a room is heated,
the humidity may fall. To increase
this humidity to the level necessary
for comfort may cause a severe
strain on the nasal mechanism.
Olfaction Discharge
Olfaction as a function may be
influenced in various ways.
For example, obstruction from
inflammation changes may
prevent air reaching the
olfactory area.
Sometimes toxic or infective
conditions or head injury
damage the nerve endings and
destroy or alter the sense of
smell.
So if the patient has smell loss he
suffer from:
Respiratory hyposmia or
Essential hyposmia.
Vocal Resonance Discharge
In case of nasal obstruction
the vocal resonance nasal
function is disturbed. And
the voice of patient
obtains the nasal
intonations or twang.
There are two kinds of twang:
1. Closed Twang (due to
nasal obstruction)
2. Opened Twang (due to
pathological associated
between nasal and oral
cavities (cleft palate,
palate paralyses)
Deformities of the Nose
Nose is the center of face. The form of the
external nose influence on the appreciation
of the appearance
Paranasal sinuses
There are eight air sinuses situated around and near the nasal cavity
(4 pairs):
1.
Maxillary sinuses
2.
Frontal sinuses
3.
Ethmoidal sinuses (is divided into anterior and posterior)
4.
Sphenoidal sinuses.
Paranasal Sinuses Functions
 Vocal-resonance.
 They are like thermos bottle
defend our brain against over
high and low temperature.
 They are protect the brain and
the eyes at the time of head
injury (like air pillow of the
car).
 They are the strong barrier that
prevent vitally important
structures (cranial cavity and
orbita) from the spreading of
the infection
Paranasal Sinuses
 The anterior group
(maxillary, frontal and anterior
ethmoidal cells) drains into
the
middle meatus
 The posterior group
(posterior ethmoidal cells
and sphenoidal sinus) drains
into the
superior meatus
 Into the inferior meatus
drains the naso-lacrimal
duct
Paranasal Sinuses
It should be noted that,
while the inferior and
middle meatuses are
open at both ends, the
superior meatus is
clothed at the anterior
end. This means that
pus from the posterior
group of sinuses will
not be seen on
anterior rhinoscopy.
Paranasal Sinuses in Children
 There is only well
developed ethmoidal
sinus in newborn. The
other sinuses are
underdeveloped.
 The development of
maxillary sinus comes
to the end to 4-5 years
of life.
 The frontal sinus has
the longest period of
development – until to
11-13 years of life
The Pharynx
The pharynx
comprises three
parts — the
nasopharynx, the
oropharynx and the
hypopharynx.
The Pharynx
The nasopharynx is situated
above to a line at the level of
the soft palate .
The oropharynx is situated below
this line and extends to the level
of the tip of the epiglottis.
the hypopharynx commences at
the level of the tip of the
epiglottis and extends to the
level of the cricoids' cartilage
The Pharynx
It has 7 holes to connect with
neighboring organs:
 1. Two choanae (with
nasal cavity).
 2. Two holes of auditory
tube
(with
tympanic
cavities).
 3.
Throat (with oral
cavities).
 4. Aperture of larynx.
 5. Aperture of esophagus.
The Nasopharynx
At the junction of the roof and
the posterior wall is situated
the aggregation of lymphoid
tissue called adenoids or
pharyngeal tonsil. Anteriorly
the nasopharynx is in
continuation with the
posterior choanae of the
nose, with the posterior ends
of the three turbinates on
each side and the posterior
edge of the nasal septum in
the midline On the lateral
wall there are the openings
of the Eustachian tubes
Behind these are the
aggregation of lymphoid
tissue called tonsil of torus
tubaris
The Nasopharynx
The pharyngeal
tonsil often becomes
overlarge in children
of 5-6 years old. It
may block choanae
and cause nasal
obstruction.
The Oropharynx
Nasopharynx and
oropharynx are separated by
the strong mobile,
membranous-muscular soft
palate. The uvula hangs
from the soft palate in the
midline. From the palate
stretch down on each side
two folds of mucous
membrane and muscle to
meet the side of the tongue.
These are the pillars of the
fauces; they are known as
an anterior and posterior
palatine arches.
The Oropharynx
Between the palatine
arches there are the
faucial tonsils,
while below the
tonsils, into the base
of the tongue, are
masses of lymphoid
tissue which are
called the lingual
tonsil
The Oropharynx
On the posterior wall
of the oropharynx
are many little
aggregations of
lymphoid tissue
which are liable, in
certain conditions, to
enlarge and become
inflamed.
The Lymphoid Circus Of
Pharynx
It consist of 6 tonsils (3 – in nasopharynx,
3 – in oropharynx)
 The two faucial (or palatine) tonsils
 The two tonsils of torus tubaris
 The one pharyngeal tonsil (adenoids)
 The one lingual tonsil
The Hypopharynx
This is the part of the pharynx which lies
level with the larynx. Between the
base of tongue and front of the
epiglottis are found two spaces
which are known as the valleculae.
They are divided in the midline by
the glosso-epiglottic ligament and
bounded posteriorly by the
pharyngo-epiglottic ligaments.
These are folds of mucous
membrane which are attached to
the posterior part of the base of the
epiglottis. Behind these ligaments
commence the pyrifarm fossae —
one on each side.
The Hypopharynx
These are folds of mucous
membrane which are
attached to the
posterior part of the
base of the epiglottis.
Behind these ligaments
commence the pyrifarm
fossae — one on each
side.
The Larynx
The larynx consists of a
cartilaginous framework
which is bound together
by ligaments and
covered with muscle
and mucous
membrane. The
cartilages of the larynx
are usually spoken of
as 'paired' and
'unpaired' cartilages
The Larynx
The paired cartilages:
1. the arytenoid cartilages;
2. the wedge-shaped
cartilages;
3. the corniculate
cartilages.
The unpaired cartilages
4. The thyroid cartilage
5. the cricoid cartilage
6. The epiglottis
The Larynx
In the interior of the larynx
two folds of mucous
membrane are
stretched from front to
back. They are rounded
and pink in colour, and
are called the false
cords. Inferior to them
is an opening into the
space known as the
ventricle. The lower lip
of the ventricle is
formed by a muscular
bundle which is the true
vocal cord
The Larynx
Seen from
above, the
cord looks
narrow and
white.
The spaces of larynx
 The vestibulum of laryngis (above the false cords).

The middle space (between false and vocal cords).
 The subglottic space (below the vocal cords) - which is the
narrowest part of the larynx
The view in laryngoscopy






1 – the arytenoid cartilage
2 – the arytenoid-epiglottis
ligament
3 – the pyrifarm fossae
4 – the ventricle of larynx
5 – the epiglottis
6 – the vocal cords