2. DEVELOPMENT OF NOSE
• 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.
3. • Olfactory placodes on the frontonasal process become depressed to form
olfactory pits which later form nasal cavity.
DEVELOPMENT OF NOSE
5. EXTERNAL NOSE
• External nose is shaped like a pyramid with its root up and
base directed downwards
• Consists of osteocartilagenous framework covered by muscle
and skin.
6. ▪ Osteocartilagenous framework:
• Upper 1/3 – bony
• Lower 2/3 – cartilagenous
• Bony frame work
• a) Nasal bone
• b)Nasal processes of frontal bone
• c) Frontal processes of maxilla
7. Cartilagenous framework
• Upper lateral cartilages
• Lower lateral cartilages (alar cartilages)
• Lesser cartilages (sesamoid cartilages)
• Septal cartilage
Nasal valve: Formed by lower edge of upper lateral cartilages, the
anterior end of inferior turbinate and adjacent nasal septum.
8. Nasal musculature:
. Procerus
.Nasalis (transverse and alar part)
.Levator labi superioris alaque nasi
.Anterior and posterior dialator naris
. Depressor septi
Nasal 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
9. INTERNAL NOSE
• It is divided into right and left nasal cavities by nasal septum
• Each nasal cavity consists of
• Skin lined portion – vestible (contains sebaceous glands, hair follicles,
vibrissae)
• Mucosa lined portion –nasal cavity proper
• Nasal cavity proper: bounded by lateral wall, medial wall, roof and a
floor.
10. Floor: Formed by
Palatine process of maxilla (anterior 3/4th)
Horizontal process of palatine bone (posterior 1/4th)
Roof: formed by
Anterior sloping part by nasal bones
Posterior sloping part by body of sphenoid
Middle horizontal part by cribriform plate of ethmoid through which olfactory nerves enter
the nasal cavity
12. Nasal septum consists of three parts
Columellar septum
Membranous septum (lies between columella and caudal border of
septal cartilage)
Septum proper: consists of osteocartilagenous framework covered
with nasal mucous membrane
13. Septum proper: principal constituents
• Perpendicular plate of ethmoid postero-superiorly
• Vomer infero-posteriorly
• Septal cartilage (quadrilateral cartilage)
These articulate with following bones to complete the septum
• Superiorly-frontal bone, nasal bone, rostrum of sphenoid.
• Inferiorly anterior nasal spine of maxilla, nasal crest of maxilla and
palatine bones
14. BLOOD SUPPLY OF NASAL SEPTUM
• By both the external and internal Carotid systems
• Internal Carotid System
1. Anterior ethmoidal artery } Branches of ophthalmic artery
2. Posterior ethmoidal artery }
• External Carotid System
1. Sphenopalatine artery (branch of maxillary artery) gives nasopalatine and
posterior medial nasal branches.
2. Septal branch of greater palatine artery (branch of maxillary artery).
3. Septal branch of superior labial artery (branch of facial artery).
15. LITTLE'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.
16. Nerve supply of medial wall of nose
• Olfactory nerves—supply the upper part (one-third) just
below the cribriform plate.
• Internal nasal branch of the anterior ethmoidal nerve, a
branch from nasociliary—supplies the anterosuperior part
• Nasopalatine nerve, a branch of pterygopalatine
ganglion—supplies the posteroinferior part.
• Medial posterior superior nasal branches of
pterygopalatine ganglion—supply the posterosuperior part.
• Nasal branch of greater palatine nerve—supplies the
posterior part.
• Anterior superior alveolar nerve, a branch of maxillpar
nerve—supplies the anteroinferior part.
