The nose

Lecture (1). د.عماد ناظم الكواز
2/10/2018
The Nose

External Nose:

The external nose is pyramidal in shape occupying the central part of the face and it is the most common organ subjected to trauma.
The apex of the nose (tip) continue cephalically as the (dorsum) which end by the (root ) of the nose.
At the lower part we have two opening (nostriles ) bounded by (ala
nasi )laterally and (columella) medially .
The skin of the external nose is thin over the dorsum & become thicker with more sebaceous gland over the tip.

Nasal Skeleton:

It is supported by bones and cartilages ( upper 1/3 is bony &lower 2/3 is cartilaginous.
Bony part:
1/ Two nasal bones
2/ Frontal(nasal) process of
maxilla
3/ Nasal process of frontal bone
Cartilaginous part:
1/ Upper lateral cartilage
2/ lower lateral cartilage(alar )
3/ Septal cartilage (unpaired)
Nasal Cavity
1) Nasal Vestibule
It is the entrance in to the nasal cavity (about 1st one cm)& enclosed by the alar cartilage.It is lined with skin which bears tough hair called vibrissae.
It ends at the muco-cutaneous junction.
2) Nasal Cavity Proper
Two cavities separated by septum.extending from anterior nares to the nasopharynx through posterior choana.The nasal cavity has its axis at right angle to the face.
Histologically the nasal cavity lined with :
lower part ( vestibule) : Stratified Squamous Epithelium / Skin .
Middle (major) part : Respiratory Epithelium / Pseudo- stratified Columnar Ciliated Epithelium.
Upper part ( olfactory area): Olfactory Neuro-epithelium which is a special sensory epithelium golden-yellow in color from which about 20 olfactory nerves pierce the cribriform plate and pass to the olfactory bulb.
Boundaries of nasal cavity:
Roof: Cribriform plate of Ethmoid bone.
Floor: Maxilla and palatine bones.
Medially: Nasal septum.
Laterally: There is a system of shelves(turbinates), under each there is a groove (meatus).


MEDIAL NASAL WALL(Nasal Septum)
Is the midline stracture that forming the medial
wall of the nasal cavity, It is made from bony
part posteriorly and cartilage anteriorly.
The cartilagenous part called Septal (Quadrilateral)
cartilage.
The bony part made from the perpendicular plate
of ethmoid posterosuperiorly & the Vomer
posteroinferiorly.
The covering mucosa of the septum is called mucoperichondrium when it overlies the cartilage and mucoperiostium when it overlies the bony part.

Lateral nasal wall:

It shows 3 turbinates made up of bone coversd by vascular mucoperiostium and respiratory epithilium .
The superior and middle turbinates are part of ethmoid bone while inferior turbinate is a separate bone
.
The inferior turbinate:
Is yhe largest& most vascular one.
The inferior meatus below receive the opening of nasolacrimal duct.

The middle turbinate :

Middle in size and site.
it is the most important clinically because most of the para-nasal sinuses (frontal, anterior Ethmoid and maxillary ) drain into middle meatus .
it has a relatively complex anatomy most affected by diseases(Osteomeatal Complex) .


Osteomeatal Complex:
It is the area of drainage of anterior group of sinuses.
Presnt in the middle meatus between: Lamina papyracea laterally and middle turbinate medially.
It shows the following structures:
Uncinate process.
Bulla ethmoidalis.
Hiatus semilunaris.
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The superior turbinate:

It is the smallest one.
Superior meatus below it.
Posterior ethmoid sinus open in the superior meatus.

Spheno-ethmoidal recess:

Small area above the superior turbinate.
It receive the sphenoid sinus ostium.

Blood supply of the nose :

 1. Sphenopalatine artery (maxillary).
2. Greater palatine artery (maxillary). (External carotid artery)
3. Superior labial artery (facial).
4. Anterior ethmoidal artery (ophthalmic artery). (Internal carotid artery)
5. Posterior ethmoidal artery (ophthalmic artery).
At the antero-inferior part of the nasal septum there is an area of vascular anastamosis called the " Little's area" which contain ( Keissel-Bach's plexus) where four vessels anastamose:
Sphenopalatine A. (maxillary).
Greater palatine A. ( maxillary).
Superior labial A. ( facial).
Anterior ethmoidal A. ( ophthalmic).
It is the most common site of epistaxis, specially in children.
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Venous Drainage:
via facial and ophthalmic veins;the latter drains to the cavernous sinus.
Hence infection in dangerous triangle may be complicated by cavernous sinus thrombosis.

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Nerve Supply:
Sensory:
1) anterior ethmoidal ( from ophthalmic branch of trigeminal)
2) sphenopalatine ( maxillary branch of trigeminal )
Secretomotor:
Vidian nerve (nerve of pterygoid canal) which is formed by the junction of the
greater petrosal nerve, a branch of the facial nerve (parasympathetic) and the
deep petrosal nerve (sympathetic) derived from the sympathetic plexus on the
internal carotid artery .
Greater petrosal nerve (parasymp.) dilates blood vessels + enhance gland secretion.
Deep petrosal nerve (symp.)  constricts blood vessels.
Olfactory: from olfactory nerve

Paranasal Sinuses

Air-filled cavities inside facial bones lined by mucosa that is continuous with nasal mucosa and communicate with nasal cavity by special ostia . all sinuses are paired & devided in to anterior and posterior groups.


Frontal
Maxillary Anterior group
Anterior ethmoid

Posterior ethmoid Posterior group

Sphenoid
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Maxillary Sinus (Antrum of Higmore):

The largest one.
Pyramidal in shape with base towards lateral wall of nose and apex directed laterally into the zygoma.
Boundaries: Its roof is the floor of the orbit and its floor lies over the 1st premolar 3rd molar teeth, the cheek anteriorly while the pterygopalatine fossa posteriorly.
The ostium of the sinus is sited high in the medial wall and hence drainage is dependent on ciliary action and not gravity.


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Frontal Sinus

The sinus is not present at birth but appear at the age of 4 years.
The roof of the orbit forms the floor of the frontal sinus while posteriorly related to the anterior cranial fossa.
It drain to the middle meatus through frontal recess.


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Ethmoid Sinuses

Divided in to anterior & posterior groups.
Anterior drain to the middle meatus.
Posterior drain to the superior meatus.
They lie between nasal cavity medially and orbit laterally where it is separated from orbit by" lamina papyracea" the thinnest bone in the body .
They are bounded superiorly by anterior cranial fossa.

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Sphenoid sinus
This sinus occupies the body of the sphenoid bone.
The pituitary gland is located on its roof in the sella turcica.
whereas the lateral wall is in contact with the cavernous sinus, internal carotid artery, and II, III, IV, V and VI cranial nerves.
It is drained into the sphenoethmoidal recess.
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Physiology of the nose:

Respiration.
Olfaction.
Vocal resonance.
Protective function by:
Filtration of inspired air by vibrissae and mucosa.
Humidification and warming of inspired air.
Reflex sneezing.
Ig A and lysozyme of nasal mucosa.


Physiology of the Paranasal Sinuses
Air conditioning of the inspired air.
Reduce the weight of the skull.
Vocal resonance.
Thermal insulation of the skull base.

Choanal Atresia

Definition : Congenital obstruction of the choana (posterior nasal opening(.
Aetiology : persistance of bucconasal membrane .
Types: it is either :
Membranous > Bony
Unilateral > Bilateral
Female > male .
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Clinical Presentation

Bilateral
It is a neonatal emergency leads to asphyxia because the infant is obligate nasal breather.
Observed at birth .
Bilateral nasal obstruction & discharge.
Feeding difficulty .
Paradox intermittent cyanosis (Cyanosis relieved by crying(.
Unilateral
May be passed unnoticed till childhood.
Unilateral nasal obstruction
Unilateral persistent thick excessive discharge in the affected side.


Diagnosis
Total absence of nasal air flow by mirror test and cotton test
Failure to pass a soft catheter to the nasopharynx.
Endoscopic nasal examination.
Contrast radiography.
CT scan to asses the type and thickness of atresia.

Management

Bilateral atresia:
It is an emergency.
Scure the oral airway after birth by insertion of oral airway .
prepare the infant for surgical perforation of atresia by manual perforator, rotating burr or LASER under the operating microscope.
The lumen is maintained patent either by stent for 10-12 weeks or by regular dilatation.

Unilateral atresia:

It is regarded as an elective condition.
The surgery postpond till pre school age.

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