Anatomy of Nose and Paranasal Sinuses

1. Anatomy of Nose
Zeeshan Ali
M-1036

2. External Nose
Internal Nose
Musculature of Nose
Vascular Supply, Nervous Innervation and Lymphatic Drainage
Paranasal Sinuses

3.  External Nose
It is pyramidal in shape with its root up and the base directed downwards
Nares – external opening of nose
Choanae - open into the nasopharynx
1. Bony Part: Posterior 1/3rd is bony
1. Nasal Bone
2. Frontal Process of Maxilla
3. Nasal Part of Frontal Bone
2. Cartilaginous Part: Anterior 2/3rd is cartilaginous
1. Upper Lateral Cartilage
2. Lower Lateral Cartilage/Alar Cartilage
3. Septal Cartilage

4. • (a) Upper lateral cartilages. They extend from the undersurface of the nasal
bones above, to the alar cartilages below. They fuse with each other and
with the upper border of the septal cartilage in the midline anteriorly.
• (b) Lower lateral cartilages (alar cartilages). Each alar cartilage is U-shaped. It
has a lateral crus which forms the ala and a medial crus which runs in the
columella. Lateral crus overlaps lower edge of upper lateral cartilage on each
side.
• (c) Lesser alar (or sesamoid) cartilages. Two or more in number. They lie
above and lateral to alar cartilages. The various cartilages are connected
with one another and with the adjoining bones by perichondrium and
periosteum. Most of the free margin of nostril is formed of fibrofatty tissue
and not the alar cartilage.
• (d) Septal cartilage. Its anterosuperior border runs from under the nasal
bones to the nasal tip. It supports the dorsum of the cartilaginous part of
the nose

6.  Internal Nose
Nasal Cavity
• Extends from Nostrils externally to Choanae internally
• Nasal Septum divides Nasal Cavity into two compartments
Nasal Septum
1. Septal Cartilage
2. Perpendicular Plate of Ethmoid Bone
3. Vomer

8.  Boundaries of Nasal Cavity
• Floor
1. Palatine Process of Maxilla
2. Horizontal Process of Palatine Bone

10. Roof
1. Nasal Bone
2. Frontal Bone
3. Cribriform Plate of Ethmoid Bone
4. Sloping body of Sphenoid Bone

12. Medial Wall
1. Septal Cartilage
2. Perpendicular Process of Ethmoidal Bone
3. Vomer

14. Lateral Wall
• 3 Projections
Superior, Middle and Inferior Conchae/Vestibule
Space below each Concha is called Meatus
Spenoethmoidal Recess – Above superior concha > Sphenoid Air Sinus
Superior Meatus – Below superior concha > Posterior ethmoid sinuses
Middle Meatus – Below middle concha
I. Bulla Ethmoidalis > formed by Middle ethmoidal air sinuses
II. Hiatus semilunaris – Lies below bulla > Maxillary Sinus
Infundibulum – continuous with frontal sinus
Inferior Meatus – Below inferior concha > Nasolacrimal Duct

17. Regions of Nasal Cavities
• Each nasal cavity consists of three general regions
• Nasal vestibule
– small dilated space just internal to the naris that is lined by skin and contains
hair follicles
• Respiratory region
– Largest part of the nasal cavity
– Rich neurovascular supply
– Lined by respiratory epithelium composed mainly of ciliated and mucous cells
• Olfactory region
– small, is at the apex of each nasal cavity
– Lined by olfactory epithelium which contains the olfactory receptors

18. • Vestibular Region
• From anterior nostrils to inferior
concha
• Respiratory Region
• From inferior concha to the
posterior nostril and up to the
superior concha
• Olfactory Region
• Above the superior concha up to
the roof of nose and adjoining
part of septum

19.  Musculature of Nose
1. the elevator muscle group — which includes the procerus muscle
and the levator labii superioris alaeque nasi muscle.
2. the depressor muscle group — which includes the alar nasalis
muscle and the depressor septi nasi muscle.
3. the compressor muscle group — which includes the transverse
nasalis muscle.
4. the dilator muscle group — which includes the dilator naris
muscle that expands the nostrils

21. Innervation and Vasculature of Muscles
• Facial Nerve
• Maxillary and Ophthalmic Arteries
• Anterior facial and Ophthalmic Vein
• Ophthalmic Vein drains into cavernous sinus – Septic Cavernous
Thrombosis
• Lymphatics – Along Anterior facial vein to Submandibular nodes or
Preauricular nodes

22. Nasal Skin
• The skin over the nasal bones and upper lateral cartilages is thin and
freely mobile while that covering the alar cartilages is thick and
adherent, and contains many sebaceous glands.

24. Blood Supply
(i) branches from the internal carotid artery, the branch of the anterior ethmoid artery, the branch of the
posterior ethmoid artery, which derive from the ophthalmic artery
(ii) branches from the external carotid artery, the sphenopalatine artery, the greater palatine artery, the
superior labial artery, and the angular artery.
• The external nose is supplied with blood by the facial artery, which becomes the angular artery that
courses over the superomedial aspect of the nose. The sellar region (sella turcica, “Turkish chair”) and
the dorsal region of the nose are supplied with blood by branches of the internal maxillary artery
(infraorbital) and the ophthalmic arteries that derive from the internal common carotid artery system.
• Internally, the lateral nasal wall is supplied with blood by the sphenopalatine artery (from behind and
below) and by the anterior ethmoid artery and the posterior ethmoid artery (from above and behind).
The nasal septum also is supplied with blood by the sphenopalatine artery, and by the anterior and
posterior ethmoid arteries, with the additional circulatory contributions of the superior labial artery
and of the greater palatine artery. These three (3) vascular supplies to the internal nose converge in the
Kiesselbach plexus (the Little area), which is a region in the anteroinferior-third of the nasal septum, (in
front and below)
• Veins follow Arterial Pattern

27. Nerve Supply of Nose
• • Three cranial nerves
• – Olfaction - the olfactory nerve [I]
• – General sensation - the trigeminal nerve [V],
• • Anterior - ophthalmic nerve [V 1 ]
• • Posterior - maxillary nerve [V 2 ]
• – Glands - parasympathetic fibers in the facial nerve [VII] (greater
petrosal nerve),
• • Sympathetic fibers

28. Nerve Supply
• (a) Olfactory nerves
• They carry sense of smell and supply olfactory region of nose. They
are the central filaments of the olfactory cells and are arranged into
12-20 nerves which pass through the cribriform plate and end in the
olfactory bulb

29. • (b) Nerves of common sensation
• They are:
• (i) Anterior ethmoidal nerve.
• (ii) Branches of sphenopalatine ganglion.
• (iii) Branches of infra-orbital nerve. They supply vestibule of nose both on its medial and
lateral side.
•
• Most of the posterior two-thirds of nasal cavity (both septum and lateral wall) is supplied
by branches of sphenopalatine ganglion which can be blocked by placing a pledget of
cotton soaked in anaesthetic solution near the sphenopalatine foramen situated at the
posterior extremity of middle turbinate. Anterior ethmoidal nerve which supplies
anterior and superior part of the nasal cavity (lateral wall and septum) can be blocked by
placing the pledget high up on the inside of nasal bones where the nerve enters.

31. • (c) Autonomic nerves
• Parasympathetic nerve fibres supply the nasal glands and control nasal
secretion. They come from greater superficial petrosal nerve, travel in the
nerve of pterygoid canal (vidian nerve) and reach the sphenopalatine
ganglion where they relay before reaching the nasal cavity. They also
supply the blood vessels of nose and cause vasodilation.
• Sympathetic nerve fibres come from upper two thoracic segments of
spinal cord, pass through superior cervical ganglion, travel in deep petrosal
nerve and join the parasympathetic fibres of greater petrosal nerve to form
the nerve of pterygoid canal (vidian nerve). They reach the nasal cavity
without relay in the sphenopalatine ganglion. Their stimulation causes
vasoconstriction.

32. Lymphatic Drainage
• Lymphatics from the external nose and anterior part of nasal cavity
drain into submandibular lymph nodes while those from the rest of
nasal cavity drain into upper jugular nodes either directly or through
the retropharyngeal nodes. Lymphatics of the upper part of nasal
cavity communicate with subarachnoid space along the olfactory
nerves.

33. • Lymphatics
• • Anterior regions
• – drains forward onto
• the face by passing
• around the margins of
• the nares -
• submandibular nodes
• • Posterior regions of
• the nasal cavity and
• the paranasal sinuses
• • drains into upper deep
• cervical nodes through the
• retropharyngeal nodes

34. paranasal sinuses
• four paired paranasal sinuses
• The paranasal air sinuses are lined with respiratory epithelium
• The maxillary sinuses, the largest of the paranasal sinuses, are under
the eyes, in the maxillary bones (open in the back of the semilunar
hiatus of the nose).
• The frontal sinuses, superior to the eyes, in the frontal bone, which
forms the hard part of the forehead.
• The ethmoidal sinuses, which are formed from several discrete air
cells within the ethmoid bone between the nose and the eyes.
• The sphenoidal sinuses, in the sphenoid bone.

35. Maxillary sinus
• Medial wall – This is the base of the pyramidal shaped maxillary sinus. This corresponds to the lateral wall of
the nasal cavity. This wall has its convexity towards the maxillary sinus. The central portion of this wall is
very thin and could even be membranous in places. The natural ostium is present in this wall. The natural
ostium is present closer to the roof of the sinus.
• Anterior wall – Corresponds to the cheek area of the face. This portion also constitutes the lateral wall of
the maxilla. Hence it would be appropriate to call it as antero lateral wall. The most important feature of
this wall is the canine fossa.
• Roof – Forms the floor of the orbit. This wall is thin. It is through this wall the infraorbital vessels and nerve
traverses.
• Floor – Is formed by the alveolar process of maxilla and the hard palate. The roots of the first and second
molars may reach up to the floor of the sinus.
• Posterior wall – Formed by temporal surface of maxilla and is very thick

36. Frontal Sinus
• It is shaped more or less shaped like L
• Posterior wall – Related to the anterior cranial fossa
• Floor – Is formed by the upper part of orbit
• Drains into the anterior part of middle meatus

37. Ethmoidal sinus
• Lateral wall – Is formed by the orbital plate of ethmoid. It is paper
thin and is known as lamina papyracea. It separates the ethmoid air
cells from the orbit. Infections involving the Ethmoidal air cells may
spread to the orbit via this thin plate of bone.
• Roof – It is formed by the frontal bone anteriorly, by the face of
sphenoid and orbital process of palatine bone posteriorly.

38. Sphenoid
• Superiorly – Pituitary gland
• Lateral wall – Optic nerve and internal carotid artery
• Floor – Nerve of pterygoid canal
• Infections of sphenoid sinus may involve optic nerve if the nerve is
dehiscent.

39. Functions of paranasal sinuses
• The presence of these sinuses lightens the skull
• They add resonance to speech