Anatomy of Nose & Paranasal sinuses

Dr. Khurshid PervejJunior residentDepartment of ENTGMC Patiala

NOSE - ANATOMYDEVELOPMENT

Nose develops from frontonasal process which grows between primitive forebrain and the stomodaeum.

Frontonasal process gets divided into median nasal process and two lateral process.

Primitive nasal cavities are closed at their posterior ends by bucconasal membrane which ruptures and forms choanae.

Clinical significance: choanal atresia

Olfactory placodes on the frontonasal process become depressed to form olfactory pits which later form nasal cavity.

DEVELOPMENT

External nose showing surface anatomy

Bony & Cartilaginous Anatomy of nose

Osteocartilagenous framework:

Upper 1/3rd - bony

Lower 2/3rd – cartilagenous

Bony framework

a) Nasal bones

b) Nasal processes of frontal bone

c) Frontal processes of maxilla

Cartilages of the external nose and columella

The nasal cartilages are composed of hyaline cartilage which may be ossified.

The upper cartilages are triangular flat expansions lying inferior to the nasal bones and are overlapped by them, by the adjacent frontal processes of the maxillae and by the lower lateral cartilages.

The lower lateral cartilage forms lower one third of nose.

Having medial and lateral crus meet at the tip of the nose.

Two medial crura attached in the midline and form columella.

The groove between the upper and lower lateral cartilages is known as the limen nasi, which is the site of intercartilaginous incisions.

Bony nasal septumUpper one third is bony; mainly by 2

nasal bones with some contributions by nasal spine of frontal bone and fronto- nasal process of maxilla.

Nasal bone: Wedge shaped convex and smooth

outer surface ; concave and roughened inner surface

United in midline with each other superiorly attached to nasal frontal suture, laterally with frontal process of maxilla.

ANATOMY OF NOSEEXTERNAL NOSE

Nasal musculature:a) Procerusb) Nasalis (transverse and alar part)c) Levator labi superioris alaque nasid) Anterior and posterior dialator narise) Depressor septiNasal skin: skin over nasal bone and upper

lateral cartilage is thin and freely mobile while that on alar cartilages is thick and adherent and contains sebaceous glands

ANATOMY OF NOSEEXTERNAL NOSEBlood supply: Facial artery- Alar region Ophthalmic and maxillary artery-

dorsum and lateral wall of ext nose

Venous drainage- corresponds to arterial supply in facial and ophthalmic vein.

Lymphatic drainage: Submandibular and Sub mental lymph nodes. Sometimes in buccal nodes.

Nerve supply: Sensory- Upper two divisions of

trigeminal nerve, Ophthalmic and maxillary nerve.

Motor- Facial nerve.

ANATOMY OF NOSEINTERNAL NOSE

It is divided into right and left nasal cavities by nasal septum.

Each nasal cavity consists of a) Skin lined portion-vestibule

(contains sebaceous glands, hair follicles, vibrissae)

b) Mucosa lined portion-nasal cavity proper

Nasal CavityExtends from nostrils to the post.

Choanae. Divided into two cavity by a

septum.Each nasal cavity has

◦a floor, ◦a roof, ◦a lateral wall, ◦a medial or septal wall.

ANATOMY OF NOSEINTERNAL NOSE

Nasal cavity posteriorly continues with the naso pharynx and

Narrower anteriorly than posteriorly.

Floor: Formed bya) Palatine process of maxilla

(anterior 3/4th )b) Horizontal process of palatine

bone (posterior 1/4th )

ANATOMY OF NOSEINTERNAL NOSE

Roof: formed bya) Anterior sloping part by nasal

bonesb) Posterior sloping part by body of

sphenoidc) Middle horizontal part by

cribriform plate of ethmoid through which olfactory nerves enter the nasal cavity

ANATOMY OF NOSEINTERNAL NOSE Nasal septum consists of three

parts a) Membranous septum (lies between

columella and caudal border of septal cartilage)

b) Septum proper: consists of osteocartilagenous framework covered with nasal mucous membrane

ANATOMY OF NOSEINTERNAL NOSE Septum proper: principal

constituentsa) Perpendicular plate of ethmoid

postero-superiorlyb) Vomer infero-posteriorlyc) Septal cartilage (quadrilateral

cartilage) These articulate with following

bones to complete the septum a) Superiorly-frontal bone, nasal bone,

rostrum of sphenoid.b) Inferiorly anterior nasal spine of

maxilla, nasal crest of maxilla and palatine bones

Cartilaginous and bony septum of nose

Cartilaginous and bony septum of nose

Perpendicular Plate (ethmoid)

Septal Cartilage Vomer

Crest of maxilla

Crest of palatine

Membranous septum

Nasal bone

BLOOD SUPPLY-NASAL SEPTUMLittle’s area: Situated in the antero-

inferior part of nasal septum just above the vestibule. Four arteries-anterior ethmoidal, septal branch of superior labial, septal branch of sphenopalatine and greater palatine anastamose here to form kiesselbach’s plexus.

Woodruff’s area: Venous plexus situated in the posterior aspect of nasal septum.

BLOOD SUPPLY-NASAL SEPTUM

The anterior ethmoidal branch of the nasociliary nerve and a smaller anteroinferior portion receives a branch from the anterior superior alveolar nerve.

The posteroinferior septum also

receives a small supply from the nerve to the pterygoid canal and a posterior inferior nasal branchof the anterior palatine nerve.

NERVE SUPPLY-NASAL SEPTUM

NERVE SUPPLY-NASAL SEPTUM

Nasal septum-LYMPHATIC DRAINAGE

The anterior septum drains with the external nose to the submandibular nodes while

Posterior septum drains to the retropharyngeal and anterior deep cervical nodes.

ANATOMY-LATERAL WALL OF NASAL CAVITY Lateral wall is formed bya) Ascending process of maxillab) Nasal bonec) Ethmoidd) Medial part of maxillae) Inferior turbinatef) Perpendicular plate of palatine boneg) Medial pterygoid plate

ANATOMY-LATERAL WALL OF NASAL CAVITY

Lateral wall is marked by three bony projections called turbinates or conchae-superior (part of ethmoid), middle (part of ethmoid), inferior (separate bone).

sometimes a fourth turbinate concha suprema may also be present.

Below and lateral to each turbinate is a corresponding meatus.

Attachments- inferior & middle turbinatesInferior turbinate: having maxillary process which articulates with the

inferior margin of maxillary hiatus. Also articulates with ethmoid, palatine and lacrimal

bone completing the medial wall of naso-lacrimal duct.

Medial turbinate: Most anterior attachment in the sagittal plane to the

fronto-nasal process of maxilla and cribriform plate. Then it turns it turns laterally and attached in

coronal plane in the lamina papyracea. (This is called basal lamella or ground lamella).

Most posterior attachment in the horizontal plane along the lamina papyracea and perpendicular plate of palatine bone.

The Lateral Walls of Nasal Cavity

ANATOMY-LATERAL WALL OF NASAL CAVITYInferior meatus- nasolacrimal duct

opens in its anterior part.Middle meatus- consists of bulla

ethmoidalis, hiatus semilunaris, infundibulum. Frontal, maxillary and anterior ethmoidal sinuses open into middle meatus.

Superior meatus- posterior ethmoidal sinuses open into it.

Sphenoethmoidal recess- triangular fossa above the superior meatus. Sphenoidal sinus opens into it.

OSTEOMEATAL COMPLEX

The middle meatus is the space below and lateral to the middle turbinate, and is often functionally referred to as the osteomeatal complex. It contains the drainage pathways for the anterior ethmoids, the maxillary and the frontal sinuses.

The middle meatus is the area that is most commonly involved in the pathophysiology of chronic rhinosinusitis.

OSTEOMEATAL COMPLEX-RELATED STRUCTURESThe Maxillary Hiatus: It is bounded by:• inferior: the maxillary process of

the inferior turbinate bone;• posterior: the perpendicular plate

of the palatine bone;• anterosuperior: a small portion of

the lacrimal bone;• superior: the uncinate process and

bulla of the ethmoid.

OSTEOMEATAL COMPLEX-RELATED STRUCTURESThe ethmoidal infundibulum:It is a cleft-like, three dimensional space

in the lateral wall of the nose that belongs to the anterior ethmoid.

Boundaries: Medially: Uncinate processLaterally: Lamina papyracea of the orbitAnteriorly: Uncinate processPosteriorly: Anterior surface of

ethmoidal bulla

OSTEOMEATAL COMPLEX-RELATED STRUCTURESThe 'hiatus semilunaris’:(inferior hiatus semilunaris according to

Grunwald) lying between the free posterior margin of

the uncinate process and the anterior surface of the ethmoidal bulla.

Sickle-shaped two-dimensional space.The superior hiatus semilunaris :This cleft

between the ethmoidal bulla and the middle nasal meatus exists, when there is a marked recess posterior to the ethmoidal bulla

OSTEOMEATAL COMPLEX-RELATED STRUCTURESUncinate process- It is superior extension of the ethmoid.Anteriorly it fuses with the postero

medial wallof agger nasi cell and postero medial wall of nasolacrimal duct.

It has free superio-posterior edge.floor and medial wall of infundibulum is

formed by the uncinate process. It is approximately 3 to 4 mm wide and

1.5 to 2 cm in length.

Ethmoidal Bullathe largest anterior ethmoidal cellalternative nomenclature of torus

lateralis (lateral bulge).Sometimes a cleft is encountered

between the posterior wall of the bulla and the basal lamella of the middle turbinate, the retrobullar recess. The space between it and the ethmoidal roof is called the suprabullar recess).

THE AGGER NASIIt is the most anterior part of the

ethmoid. It is represented by a small crest

or mound on the lateral wall just anterior to the attachment of the middle turbinate.

It may be pneumatized.

Frontal recessFound in the most antero superior part

of the middle meatus.The frontal recess may be defined as

follows:• medial: middle turbinate;• lateral: lamina papyracea, lacrimal

bone;• superior: skull base;• inferior: dependent upon the

attachment of the uncinate process;• pneumatization of agger nasi cells.

Anatomical VariationsConcha bullosaNasal septal deviationParadoxic middle tubinateVariations in the uncinate processHaller or infraorbital cellsOnodi or sphenoethmoidal cellsGaint ethmoidal bullaExtensive pneumatization of the

sphenoid sinusAerated crista galli.

Sphenoethmoidal recess- triangular fossa above the superior meatus.

Lies medial to superior tubinate.Sphenoidal sinus opens into it.

Posterior Ethmoid Complex-The clefts and cells posterior to the basal

lamella. Drains into superior meatus.The sphenoid sinus ostium opens into the

sphenoethmoidal recess medial to the superior turbinate.

Lateral and posterior external of posterior ethmoidal air cells are called Onodi or Sphenoethmidal cells.

Blood Supply to the Nasal Cavity

Sphenopalatine a.

Maxillary a.

Netter, Frank H., Atlas of Human Anatomy. Ciba-Geigy Corporation, Summit, N.J. 1993. Plate 35.

Roof of the ethmoid comlex Roof formed by the cribriform plate

of the ethmoid separtes the nose from anterior cranial fossa.

Cribriform plate shows horizontal medial lamella and oblique or vertical lateral lamella.

Lateral lamella articulates with the frontal bone.

Thus the ethmoid fovea is formed medially by the cribriform plate and laterally by the frontal bone.

The length of the latral lamella and depth of the olfactory fossa are classified by kero and Kainz into three types-

Type I- 1-3 mmType II- 4-7 mmType III- 8-17 mm

Roof of the ethmoid comlex

Anterior ethmoidal artery

Blood Supply to the Nasal CavityFrom branches of the maxillary artery, one of the terminal branches of the external carotid artery.

The most important branch is the sphenopalatine artery.

The sphenopalatine artery anastomoses with the septal branch of the superior labial branch of the facial artery in the region of the vestibule.

The submucous venous plexus is drained by veins that accompany the arteries.

AUTONOMIC NERVE SUPPLY- NASAL CAVITYSympathetic supply- superior

cervical sympathetic ganglion -> internal carotid plexus -> vidian nerve -> sphenopalatine ganglion.

Parasympathetic supply- facial nerve -> greater superficial petrosal nerve -> vidian nerve -> sphenopalatine ganglion.

Nasal branches from sphenopalatine ganglion supply the nasal cavity.

SENSORY NERVE SUPPLY-NASAL CAVITY

Trigeminal nerve carries the common sensation via ophthalmic and maxillary divisions.

Special sensory (smell) carried via olfactory nerves.

Nerve Supply of the Nasal Cavity

CN I – Olfactory Nerves (SVA)Anterior

ethmoidal branch of V1

Posterior nasal branches of V2

Cut nasopalatine branch of V2 to septum

LYMPHATIC DRAINAGE-NASAL CAVITY

Lateral wall drains into submandibular lymph nodes anteriorly ; and posteriiorly lateral pharyngeal, retro pharyngeal and upper deep cervical lymph nodes.

The Paranasal Sinuses

Maxillary sinus (Antrum of Highmore)

Largest of the paranasal sinuses Pyramidal in shape Capacity- 10-20 ML boundaries-a) Medial wall- lies between the sinus and

nasal cavityb) Posterior wall- related to pterygopalatine

and infratemporal fossaec) Anterior wall- related to soft tissue of

cheekd) Roof- formed by floor of orbite) Floor- formed by alveolar process and

palate

Neurovascular supply Blood supply – Facial, Maxillary, Infra orbital and greater palatine Artery

Venous return – To the anterior facial and pterygoid venous plexus.

 Lymphatic drainage - Submandibular nodes.

Nerve supply – Maxillary division of trigeminal n. Via infraorbital superior alveolar and greater palatine nerves.

FRONTAL SINUS Situated in between inner and outer table of frontal bone Pyramidal in shape with apex upwards and base is formed by the

floor Capacity- 5-10 ML Boundariesa) Anterior wall-outer table of frontal boneb) Posterior wall- inner table of frontal

bone separates the sinus from cranial cavity

c) Floor- formed by thin bone separating sinus from orbit

d) Medial wall- forms the septum between two frontal sinuses

Neurovascular supply Blood supply - Supra orbital artery

Anterior ethmoidal arteries.Venous return - Anastomotic veins

in supra orbital notch, connecting supra orbital and supra ophthalmic veins.

 Lymphatic drainage - Submandibular nodes.

Nerve supply - Supra orbital nerve traversing the floor of the sinus.

ETHMOIDAL SINUSES Thin walled air cavities in the lateral masses of ethmoid bone. Clinically divided into anterior and posterior group Ethmoidal labyrinth has following

relationsa) Roof- ant. cranial fossa lateral to

cribriform plateb) Lateral wall- orbit, optic nerve,

nasolacrimal duct separated by thin bone called lamina papyracea

c) Inferior- maxillary sinusd) Posteriorly- sphenoid sinuse) Medially- superior and middle turbinate

Neurovascular supplyBlood supply : Sphenopalatine

artery Anterior and posterior ethmoidal artery.

Lymphatic drainage : Submandibular nodesRetropharyngeal nodes. 

Nerves : Anterior and posterior ethmoidal nerves.Orbital branches of pterygopalatine ganglion..

SPHENOID SINUS

There are 2 sinuses in sphenoid bone divided by a thin bony septum Relations- a) Laterally- cavernous sinus

containing 3,4,5,6th cranial nerves, internal carotid artery, optic nerve

b) Superiorly- pituitary gland, optic chiasma, olfactory bulb, frontal lobe

c) Inferiorly- nasopharynx and vidian nerve

d) Posteriorly- brainstem, Basilar artery

Depending upon the pneumatization of the sphenoid bone, This sinus is classified as:

A. Conchal pneumatization, with only a rudimentary sinus (2-3 percent) .

B. Presellar, in which the sinus is pneumatized as far as the anterior bony wall of the pituitary fossa ( 1 1 percent) .

C. Sellar, in which pneumatization extends back beneath the pituitary fossa ( 59 percent) .

D. Mixed (27 percent)

SPHENOID SINUS

Blood supply : Posterior ethmoidal artery.

Lymphatic drainage : Retropharyngeal nodes.

Nerve supply : Posterior ethmoidal nerve.

Neurovascular supply

Sinus Drainage Schema

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