Anatomy and Embryology of Nose

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Presenter – Dr Pulkit Agarwal
Moderator – Dr G.S.Renukananda
4th to 8th week from 5 Swellings
(Ectoderm)
Ectodermal
thickenings(5th week)
1st Arch
6th week : ectoderm from Nasal placode invaginates to form oval nasal pits
12.5 mm Enbryo stage : Maxillary prominence grows medially
Nasal pits separate from stomodeum
Intermaxillary process (fusion of medial nasal process) central tissues pushed up to
form nasal prominence
By 7th week invaginates to form nasolacrimal duct
Globular process forms
the philtrum
angles till
of medial
nasal process)
Canalisation
may(lateral
not complete
after birth
• Nasal Septum Development – 13.5 mm embryo stage (6th week)
• Fusion of maxillary to frontonasal process.
• Midline ridge from posterior end of frontonasal process forms
septum
• 6th week
• 15mm stage
Nasal pits deepen and coalesce (end of 6th week)
Primitive Choanae formed at 7th week
Primitive nasal septum is completely Cartilagenous
2 centres
Groove on which septal catilage sits
Lateral nasal processes – nasal alae and lateral nasal wall
Hard palate formed by around 8th and 9th week
Palatine shelf – Medial extensions of maxillary process
Fuses with septum forming 2 passages which opens into defintive choanae
Paraseptal Jacobsons cartilage invagination of ectoderm leads to
Vomeronasal Organ
Disappears leaving a blind tubular pouch 2 – 6mm long
Jacobsons cartilage involutes leaving small cartilagenous bulge
VNO / Jacobsons organ is first stage of the accessory olfactory system,
and contains sensory neurons that detect chemical stimuli mainly used to
detect pheromones found in many animals
Processes
 Frontonasal
 Maxillary
 Medial Nasal
 Lateral Nasal
 Mandibular
Structures
Formed
Forehead, Bridge of nose,
medial and lateral nasal
prominences
Cheeks, Lateral portion of
upper lip
Philtrum of upper lip, Crest
and tip of nose
Alae of nose, lateral nasal
wall
Lower lip and jaw
External Nose
Nasal Cavity
Nasal Septum
Lateral Wall
Anatomical Variations
Skin & Vestibule :
Skin :
Thickness of skin and soft tissue varies.
Over dorsum and side – thin and loose
Over tip & alar region – thick and adherent
Vestibule :
Anteriormost part of nasal cavity lined by stratified
squamous keratined epithelium.
Demarcated by limen nasi
Lined by coarse vibrissae, glands
Blood supply
ICA  Ophthalmic Artery
Maxillary artery
Vth  Ophthalmic nerve
 Anterior ethmoidal
External nasal nerve
(Dorsum, tip)
Vestibule of nose
ECA
VENOUS DRAINAGE
Corresponds to arteriovenous units.
Frontomedian area drains into the facial vein
Orbitopalpebral area – ophthalmic vein (cavernous sinus
communication)
LYMPHATIC DRAINAGE
Submandibular and submental nodes and sometimes buccal
nodes intervene
Nerve supply
Trigeminal Nerve
Ophthalmic Branch
Anterior Ethmoidal
External Nasal
Maxillary Branch
Nasociliary
Infratrochlear
Infraorbital nerve
Vestigial
importance
Depresses Septum
Tip of nose
Expandes nares during forced
inspiration
Transverse – Pyriform
aperture to Dorsum of nose &
Contracts nasal aperture
Alar – beneath nasomaxillary
suture line via short thin
tendon to skin of nasal alae
Contraction causes shortening
and dilation of Nostril
Continuation of Frontalis
Shortens nose on contraction
and also movements in region
of eyebrows hence aka
Depressor Glabellae
Frontal process of maxilla
Blends with lateral crus of
lower lateral cartilages &
pulls it superiorly
Also pulls lips superiorly
helping in dilation
framework
Bony :
Nasal Bone
Nasal process of frontal Bone
Frontal process of maxilla
Cartilagenous:
Paired upper lateral cartilages
Septal Cartilage
Paired lower lateral cartilage / Greater alar cartilage
Minor accessory alar cartilages
Nasolacrimal Suture
Supported by Nasal
Spine and perp. Plate
of ethmoid
Upto
15mm
Nasal bones
are supporetd
by perp plate
of ethmoid
and nasal
spine both of
which groove
the bone
Overlapped by Nasal bone,
Maxilla, Alar cartilage
(Fibrous Cartilage)
Limen Nasi
(Intercartilagenous
Incisions)
Hyaline cartilages which may be ossified & prevent collapse of vestibule
Overlapped by Nasal bone,
Maxilla, Alar cartilage
(Fibrous Cartilage)
Limen Nasi
(Intercartilagenous
Incisions)
Medially continuous with septal cartilage which is bifid in this region
Medial Crus
Lateral Crus
Medial is loosely attached in midline anterior to Quadrangular Cartilage
& contributes to Columella (area from tip to philtrum)
Medial Crus
Lateral Crus
Lower margin of lateral ascends away from margin of Nostril
Medial Crus
Lateral Crus
3 – 4 sesamoid cartilages present
Nasal Cavity
Extension
Vertical
Extent
(Broader)
HORIZONTAL PROCESS
Each half has a floor, roof lateral and medial wall.
Floor – concave, Ant 3/4th – Palatine process of maxilla and posterior 1/4th
by horizontal process of palatine bone
12mm behind ant end, mucous memb dips overlying incisive canal
Contains terminal branches of Nasopalatine nerve, greater palatine artery &
short mucosal stensons canal
Olfactory epithelium
Roof :
Frontonasal
Ethmoidal
Sphenoidal
Highest, Cribriform
plate of ethmoid
which is horizontal
Resp epithelium
continuous with
PNS, NLD &
nasopharynx
Medial Wall = Septum
Lateral Wall = Lateral Wall of Nose
Nasal septum
Bones –
Perpendicular plate of ethmoid
Vomer
Two bony crests of the
maxilla and palatine
Rostrum of sphenoid
Nasal spine of frontal bone
Cartilages –
Quadrilateral cartilage
Upper and lower lateral
cartilages contribution
Vomeronasal Cartilage
Membranous septum
QUADRANGULAR CARTILAGE
3 – 4 mm centrally and 4 – 8 mm anteroinferiorly (footplate)
Above dome of lower lateral cartilages, upper angle expanded
forming anterior septal angle
Perp Plate of ethmoid
forms superior and anterior bony septum
Above is cribriform plate and cristae galli
Grooves nasal bones
vomer
Posterior and inferior septum
With 2 alae articulates with rostrum of
sphenoid, forms vomerovaginal canals
which transmit pharyngeal branch of
maxillary artery
Inferiorly – with both crests
Anterior – perp plate & septal cartilage
Post free edge
of vomer
Blood Supply
Posteroinferior septum and anteroinferior face
of sphenoid sinus
& posterior halves of middle & inf turbinates
b/o maxillary artery b/o ECA
Blood Supply
Supplies anteroinferior portion entering the
nasal cavity via incisive canal
b/o maxillary artery b/o ECA
Blood Supply
Supplies anteroinferior portion entering the
nasal cavity via incisive canal
b/o Facial artery b/o ECA
Blood Supply
b/o ICA
Sinusoidal system in nasal submucosa under autonomic control
described well with turbinates but also seen in septum adjascent
to inferior turbinate and most anterior part of septum
Related to control of airflow in nasal cavity
In 2/3rd seen in posterior septum
Nerve supply
Maxillary nerve (V2) supplies majority of septum
Nasopalatine nerve, posterosuperior nasal branch of maxillary
nerve supplies bulk of bony septum entering via sphenopalatine
foramen.
Anterosuperior – anterior ethmoidal branch of nasocilairy nerve
(V1 branch)
Small Anteroinferior area supplied by anterior superior alveolar
nerve
Anterior superior
alveolar nerve
b/o pterygopalatine ganglion and carries both
sensory and parasympathetic fibres
& also Vidian nerve
Nerve supply of septum
Sensory nerves accompanied by postganglionic sympathetic
nerves to blood vessels and postganglionic parasympathetic
secretomotor fibres pass to glands with the branches from the
pterygopalatine ganglion
Olfactory, respiratory and stratified squamous keratinised
epithelium
Surface area increased by cilia on respiratory cells
Nerve fibres from olfactory receptors are slim and bundled
together in sets of 20 to pass through cribriform plate
Carries dura, pia along
Shearing may lead to CSF leak or
destruction of olfaction
LYMPHATIC DRAINAGE
Anteriorly – Submandibular LN
Posteriorly – Retromandibular &
deep cervical LN
Lateral wall
Roof of posterior choanae
1 cm
Straighter
Atrium – Structureless area
Shows bulge anterior to middle turbinate formed by agger nasi
cells
Ridge from agger nasi to apex of superior border of inferior
turbinate which overlies NLD
3 scrolls of turbinates. Occasionally supreme turbinate.
Sphenoethmoidal recess above superior turbinate which forms
niche between posterior ethmoidal cells and sphenoidal cells
Fossa of rosenmuller forms a deep cleft behind torus tubaris
Attachments of middle turbinate :
Anterior 1/3rd – cribriform plate at jnct in saggital plane also
takes a small anterior attachment to frontonasal process(maxilla)
Middle 1/3rd – lamina papyracea in coronal plane (ground
lamellae)
Posterior 1/3rd – to lamina papyracea and the perpendicular plate
of the palatine bone extending upto the roof of posterior choanae
Behind middle turbinate, most anteriorly – Uncinate process
Separated from well pneumatized ant ethmoidal cell (bulla) by
hiatus semilunaris inferioris.
Hiatus semilunaris leads into infundibulum
Osteomeatal Complex
As per Naumann :
Osteomeatal complex is complex microarchitectural pathway in
ethmoid labyrinth that drains anterior group of paranasal sinuses
and consists of frontal recess, ethmoid infundibulum, hiatus
semilunaris, uncinate process, bulla ethmoidalis and middle
meatus
Uncinate process – sickle shaped, Horizontal and vertical parts
& intermediate transitional part
Retrobullar recess – Between bullae and ground lamellae
Suprabullar recesss – If bulla doesn’t extend till skull base
Together form space above and behind the bulla called Sinus
Lateralis of grunwald which opens in middle meatus via Hiatus
semilunaris superioris
Boundaries :
Roof
: Ethmoid fovea
Floor
: Ethmoid bulla
Posteriorly : Ground lamella
Anteriorly : Frontal recess
Laterally
: Lamina papyracea
Medially
: Middle turbinate
Infundibulum leads into the frontal recess
Frontal Recess :
Boundries
Anteriorly : Agger Nasi cells (a part of Frontal recess)
Posteriorly : Bulla Ethmiodalis (a suprabullar recess will open in
posterior wall of frontal recess)
Laterally : Lamina Papyracea
Medially : Middle turbinate
Superiorly : Opens via the frontal ostium into the frontal sinus
Frontal sinus opening is funnel shaped (FI) in posteromedial
floor of sinus. Hour glass config.
Upper end of Uncinate lies in frontal recess.
Large no of anatomical variations but 80% attached to lamina
papyracea in form of dome
Dome like attachement of uncinate in frontal recess described
by Stammberger – eggshell in inverted cup
Recess enclosed within this dome is called recessus terminalis
In this case frontal sinus opens medial to uncinate process
Well hidden by the uncinate process lies an opening of the
maxillary sinus
Normal ostium – 3D, Ovoid and tunnel like
Accessory osteum – 2D, Circular
Relations of maxillary ostium are : Inferiorly is the inferior
turbinate, 1 to 2 mm superiorly is the lamina papyracea and the
orbit, posteriorly is the posterior fontanelle, 0.5 cm anteriorly
lies the nasolacrimal duct
Anterior fontenelle – AI to uncinate
Posterior fontenelle – PS to uncinate
Both are just double layer of mucous membrane without
underlying bone, thus if memb deficient can lead to accessory
ostia
Bulla may drain into the middle meatus/hiatus semilunaris/
sinus lateralis
Frontal sinus drains into frontal recess medial or lateral to
uncinate process depending on the mode of attachment of the
uncinate process or suprabullar recess if present
Maxillary sinus – always in infudibulum
Sphenoid sinus – Sphenoethmoidal recess
Meatal Drainage
Inferior meatus :
NLD (Hasners valve)
Middle meatus :
Frontal
Anterior ethmoidal
Maxillary
Superior meatus :
Posterior ethmoidal
Sphenoethmoidal recess :
Sphenoid
Arteries Of lateral and medial wall of Nose
Artery
Branch of
Supplies
Anterior ethmoidal & Posterior
Ethmoidal arteries
Ophthalmic artery(ICA)
Ethmoid and frontal sinuses, roof of the
nose, upper part of lateral wall and
septum
Sphenopalatine artery
Maxillary artery 3rd part (ECA)
Mucous membrane, superior and
middle meatus, conchae and septum
Greater palatine artery
Maxillary artery (ECA)
Posterior part of lateral nasal wall (also
anteroinferior end of septum)
Superior Labial
Facial artery (ECA)
Region of vestibule of nose
Infraorbital artery, anterior and posterior superior alveolar
arteries b/o Maxillary artery supply Maxillary sinus
Pharyngeal branch of maxillary sinus supplies sphenoid sinus
Nerve supply :
(V1)
(V2)
Anatomical Variations
DNS –
AP deviations best seen in axial scans
Spurs at vomerocartilagenous junction – Coronal scans
Near OMC may lead to impaired drainage of sinuses
Concha bullosa or HIT on roomy side may compromise OMC
Septum may be pneumatised
Agger Nasi cells –
Can be hypoplastic or prominent leading to displacement of anterior
attachment of middle turbinate posterosuperiorly
Uncinate process –
Hypoplastic / laterally bent – Infundibulum narrow space difficult to
enter
Medially bent so much so to resemble anterior wall of bulla, or may
be curled upon itself to appear like a duplicated middle turbinate
•
•
•
•
Variations attachment of Uncinate –
Skull base
Middle turbinate
Insertion of middle turbinate
May lie free in the middle meatus
May be pneumatised
Uncinate if attached to skull base, frontal sinus drains into
infundibulum and therefore diseases from the frontal sinus can spread
directly to the maxillary sinus and vice versa
Middle turbinate :
Pneumatised – concha bullosa (either from agger nasi/frontal reces or
from anterior ethmoidal cells)
Concha may obstruct airway, affect drainage of secretions and lead to
chronic infections of sinuses
Occasionally middle turbinate may pneumatise the vertical lamella of
the middle turbinate to produce what is called the intralamellar cell of
Grunwald
May take a paradoxical sharp bend laterally, often bilaterally leading
to blockade of infundibulum
Can sometimes curl upon itself to produce a concavity within it called
turbinate sinus
Ethmoidal bulla :
Hypoplastic or non pneumatised hillock
May be excessively pneumatised abutting against uncinate process
anteriorly or the middle turbinate compromising infundibulum or
middle meatus respectively
The sinus lateralis may extend laterally to pneumatise the roof of the
orbit thus forming the supraorbital ethmoid cell. This cell is seen in
coronal CT scan at the level of the bulla behind the frontal sinus
Ethmoid Air Cells :
The anterior and posterior ethmoid air cells may pneumatise
surrounding bones like lacrimal bone, maxilla, frontal bone, sphenoid
to produce varying patterns of pneumatisation
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