anatomy of nose & paranasal sinuses dr. vishal sharma

Anatomy of Nose &

Paranasal SinusesDr. Vishal Sharma

Development of nose

• Face develops from 5 projections: frontonasal

process (ectoderm over forebrain) + 2 maxillary

processes + 2 mandibular processes (1st arch)

• An ectodermal olfactory placode divides fronto-

nasal process into medial nasal & lateral nasal

process, which give rise to external nasal skeleton

• Olfactory placode deepens into olfactory pit & later

olfactory sac which forms nasal cavities

• Nasal septum develops from mesodermal tecto-

septal expansion from Rathke’s pouch

External Framework

External Framework• Nasal Bone

• Frontal Process of Maxilla

• Upper Lateral Nasal Cartilage

• Lower Lateral Nasal (Alar) Cartilage

• Septal Cartilage

• Lesser Alar (Sesamoid) Cartilages

Internal Nose

• Openings: Anterior nares & posterior

nares (Choanae).

• Vestibule of nose: lined by skin

• Nasal cavity proper:

Lateral Wall Medial Wall (Septum)

Roof Floor

Nasal Septum

Nasal Septum

Nasal Septum

1. Septal cartilage 7. Medial alar crus

2. Ethmoid plate 8. Upper lateral cartilage

3. Vomer 9. Nasal bone crest

4. Palatine crest 10. Frontal spine

5. Maxillary crest 11. Sphenoid rostrum

6. Vomeronasal 12. Membranous septum

cartilage

Lateral Nasal Wall

3 - 4 bony conchae covered with mucosa

to form turbinates. Space below & lateral

to turbinate is called meatus.

Middle meatus contains a round bulla

ethmoidalis separated from uncinate

process by hiatus semilunaris that leads

to a funnel shaped ethmoidal infundibulum.

Meatal Drainage1. Inferior meatus: Nasolacrimal duct ( guarded at its end

by a mucosal valve called HASNER’s valve )

2. Middle meatus:

a. Frontal

b. Anterior ethmoid

c. Maxillary (natural + accessory ostia)

3. Superior meatus: Posterior ethmoid

4. Spheno-ethmoidal recess: Sphenoid

Ostio-meatal Complex

Ostio-meatal Complex

Complex micro-architectural pathway in ethmoid

labyrinth that drains anterior group of paranasal

sinuses. Consists of: frontal recess + ethmoid

infundibulum + hiatus semilunaris + uncinate

process + bulla ethmoidalis + middle meatus.

O.M.C. pathology leads to infection of all anterior

paranasal sinuses (Naumann).

Variants in O.M.C.1. Concha bullosa (pneumatized M.T.)

2. Paradoxically curved middle turbinate

3. Medially turned uncinate process

4. Large bulla ethmoidalis

5. Haller’s cell in orbital floor

6. Agger nasi cell anterior to M.T.

7. Onodi Cell with dehiscent Optic Nerve

8. Mucosal pathology

Concha bullosa

Concha bullosa

Paradoxically curved M.T.

Paradoxically curved M.T.

Medialized Uncinate Process

Large bulla ethmoidalis

Haller cell

Agger nasi cell

Onodi cell with dehiscent optic nv

Mucosal disease

Blood Supply1. Sphenopalatine artery (main artery)

2. Greater palatine artery

3. Superior labial artery

4. Anterior Ethmoidal artery

5. Posterior Ethmoidal artery

1, 2, 3 & 4 form Kiesselbach’s plexus over

Little’s area on anterior septum

Venous drainage

Ethmoidal veins: ophthalmic veins

cavernous sinus

Sphenopalatine vein: pterygoid plexus

maxillary vein 

Woodruff’s venous plexus: present on lateral wall

near posterior end of middle

turbinate

Retro-columellar vein: behind columella

Sensory Nerve Supply

• Long & short Nasopalatine nerves

• Greater palatine nerve

• Infra-orbital nerve branches

• Anterior ethmoidal nerve

• Olfactory nerve

Autonomic Nerve Supply• Deep petrosal nerve (sympathetic) + greater

superficial petrosal nerve (para-sympathetic)

vidian nerve pterygo-palatine ganglion nasal

glands

• Sympathetic stimulation vasoconstriction +

ed nasal secretions

• Para-sympathetic stimulation vasodilatation +

ed nasal secretions

Lining Epithelium

• Skin: over nasal vestibule

• Olfactory epithelium: upper 1/3rd of nasal cavity

above superior turbinate

• Respiratory epithelium (pseudo-stratified

ciliated columnar): rest of nasal cavity +

paranasal sinus

Lining Epithelium

Lymphatic Drainage

1. External nose & anterior nasal cavity

submandibular lymph nodes

2. Remaining nasal cavity

upper deep cervical lymph

nodes

3. Nasal roof (dangerous area of nose)

subarachnoid space along olfactory

nv

4. P.N.S. retropharyngeal & J.D. node

Paranasal Sinuses• Anterior group:

frontal

anterior ethmoidal

maxillary

• Posterior group:

posterior ethmoidal

sphenoid

Development of P.N.S.

Appear first

First X-ray appearance

Reach adult size by

Maxillary At birth 4 mth 15 yr

Ethmoidal At birth 1yr 12 yr

Sphenoid 2 yr 4 yr 18 yr

Frontal 4 yr 6 yr 15 yr

Sphenoid Sinus Relations

Muco-ciliary blanket

• Goblet cells in nasal mucosa secrete a

mucous blanket; moved backwards like a

conveyer belt into nasopharynx.

• Consists of:

Superficial mucous or gel layer

Deep serous or sol layer

Muco-ciliary blanket

Muco-ciliary blanket

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