y

1. Competency covered EN 1.1
Dr. Srinivas Pennam

2.  NOSE
1. external nose
2. nasal cavity proper
1. EXTERNAL NOSE:
 Pyramidal structure
 Made up of bone and cartilage
 Root – upper angle of nose continuous with forehead
 Base of the nose directed downwards.
 Base is triangular in shape and two openings –anterior
nares
 Area btw tip & root is called dorsum of nose

3. EXTERNAL NOSE
Upper 1/3 rd (nasion
region)
Middle 1/3 rd
Lower 1/3 rd

4. Supporting frame work of nose is composed of :
 Bony skeleton:
1. Paired nasal bones
2. Paired frontal process of maxillae
3. nasal process of frontal bone
 Cartilage frame work:
1. Septal cartilage
2. Paired upper & lower lateral cartilages
3. Sesamoid (minor cartilages) - variable in no.

5. BONY PARTS
Nasal processes of
the frontal bones
Nasal bones
Frontal process
of the maxillae

6. CARTILAGINOUS PARTS
Lesser alar cartilage
Lateral nasal
cartilage
Greater alar cartilage
Dense connective
tissue

7. BASAL VEIW
Middle crus
Lateral crus
Medial crus

8. Contd..
 VESTIBULE :
1. dilated passage way leading from external nares into nasal
fossae , demarcated by limen nasi at superior margin of
lower lateral cartilage.
2. Lined by skin bearing coarse hair, sebaceous glands , sweat
glands.
3. Forms a part of dangerous area of face (retrograde venous
drainage by ophthalmic veins)
 COLUMELLA:
1. Part b/w two nasal vestibules and forms caudal end of the
septum
2. Formed by medial crura of two lower lateral cartilages

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

12.  NASAL BONES:
1. unite with each other in midline
2. Superiorly :with frontal bone-
nasofrontal suture
3. Laterally: with frontal process of
maxilla-nasolacrimal suture
4. They r supported by nasal spine of
frontal bone&perpendicular plate of
ethmoid.
5. Nasal bone is wedge shaped-convex
n smooth outer surface,concave n
roughened internally
 PYRIFORM APERTURE:
1. bounded below & laterally –maxilla
2. Above-nasal bones
3. Ant nasal spine lies in midline of
inferior border & can be of 15mm
in length

13. Cartilages of external nose & columella
 Hyaline cartilage
Prevents collapse of vestibule on inspiration
1. Upper cartilages: flat expansion lie inferior to nasal bones,
overlapped by frontal process of maxillae & lower lateral
cartilage.
2. Lower lateral cartilages : form lower 1/3 of nose ,medial crura
loosely attach to each other in midline & contribute to
columella
 Groove btw upper & lower lateral
cartilages- limen nasi, its site of
inter cartilaginous incision
 Btw 1-4(avg2-3)minor sesamoid
cartilages r found btw upper n lower
lateral cartilages

15.  Blood Supply :
 Branches of facial artery – alar region
 Dorsal br of ophthalmic artery
 Infra orbital br of maxillary – dorsum &
lateral wall of external nose.

16.  Venous drainage: 1 Frontomedian-facial vien
2 Orbitopalpabreal-opthalmic vien
 These have inter-connection to ant ethmoidal system & hence
cavernous sinus which can be of clinical significance.
 Nerve supply: sensory- 2 upper divisions of trigeminal-
opthalmic & maxillary.
 External trochlear br of opthl nerve- skin over root n dorsum
 Infra trochlear br of opthl nerve- lateral surface of root of nose
 Infra orbital br of maxillary nerve- nasal alae &skin of vestibule.
 Lymphatic drainage: Submandibular
Submental

17. Nasal Cavity
 Extends from external nares to posterior choanae
 Narrower anteriorly than posterior
 Vertically: palate to cribiform plate, broader at its base
& narrower at olfactory cleft.
 Divided into 2 by septum-individual variations
 Each half- floor
roof
lateral wall
medial wall(septum)

18. Floor :
 Concave, side-to-side,
ant to post – flat & almost horizontal.
 Composed: ant 3/4 palatine process of maxilla.
post 1/4 horizontal process of palatine bone.
Appx 12mm behind the ant end of floor is slight depression in
mucous membrane overlying incisive canal.
Contains – terminal br of naso palatine nerve.
greater palatine artery
short mucosal canal(stenson’s organ)

19. The Floor of Nasal Cavity
Palatine
process of
maxilla
Horizontal
plate of
palatine bone

20. Roof :
 Narrower, side-to-side except post
 frontonasal – nasal process of frontal bone
 ethmoidal - Cribriform plate
 sphenoidal – body of the sphenoid
 Both frontonasal and sphenoidal part of roof slope
downwards,
 highest part of NC relates to cribiform plate of
ethmoidal which is horizontal covered by olfactory
epithelium.
 Rest of NC lined by respiratory mucous membrane.

21.  Olfactory area: (dangerous area of nasal cavity)
 Laterally by superior turbinate
 medially by septum
 Superiorly by cribriform plate.
 Olfactory nerve fibres  cribriform plate  ACF
 Olfactory region – 2.5 cm2
 5o million primary sensory receptor cells
 Lined by brownish epithelium

22.  3 cell types:
 Bipolar receptor cells
 Supporting cells
consisting of microvilli
 Basal cells contain
yellow pigment

23. Nasal Septum
 Anterior membranous
 Cartilage
 Bones
Cartilagenous portion :
 Quadrilateral cartilage, with contribution from lower
and upper lateral alar cartilage – ant nasal septum.
 Quardilateral cartilage 3-4 mm thick in centre ↑ to 4-8
mm ant inf which has been termed foot plate.

25.  Superiorly :Upper margin expands & connects to upper
lateral cartilage forming anterior septal angle.
 Inferiorly: Perpendicular plate of ethmoid & vomer
and abuts maxillary spine – inferior septal angle.
 Anteriorly: Attached by thin membranous septum to
medial crura of lower lateral cartilage.

26. Bony septum
Major contribution from
 Perpendicular plate of ethmoid
 Vomer
 Palatine crest
 Maxillary crest
Small contribution from
 Nasal spine of frontal bone
 Rostrum of sphenoid
 Anterior nasal spine of maxilla

28. Bony septum
 Perpendicular plate forms sup & ant bony septum,
continuous with cribriform plate & crista galli above.
 Vomer : post & inf nasal septum and articulates by its 2 alae
with rostrum of sphenoid creating vomero vaginal canal
which transmits the pharyngeal br of maxillay artery.
 Vomer articulates
 Inf : nasal crest of maxilla & palatine bone.
Ant : perpendicular plate of ethmoid.
Post: Forms post free edge of septum.

29.  Surface area of septum 30-35 cm2.
 Deflection may develop at any septal articulation.
 Spurs may be found where the quardilateral cartilage
sends small process btw ethmoid & vomer.
 DNS more often to left than right.
 Men than women

30. Blood supply
 External & internal carotid artery
 Anterior superior : Anterior ethmoid br of opthalmic artery
 Anterior inferior: greater palatine br of maxillary artery
 Posterior inferior: Sphenopalatine br of maxillary artery
 Membranous part of septum: Septal ramus of sup labial br of
facial artery
 Ant inf part of septum highly vascular

33. KESSELBACHS PLEXUS
• These arteries are
• (mnemonic –LEGS)
• Superior Labial
• Anterior Ethmoidal
• Greater palatine
• Sphenopalatine
• Little's area, is a region in the anteroinferior part
of the nasal septum, where there is confluence of 4
arteries forming this plexus.

34.  Venous drainage:
Ant sup-Sup opthalmic vein
Post inf-Pteryoid Venous plexus
Membranous part of septum-Internal
jugular vein through facial vein
 Infections extend to cavernous sinus via deep facial
vein & pterygoid venous plexus → Dangerous area of
face
 Upper part of septum-Veins accompany the olfactory
nerve & drain into inf cerebral veins, sup sagittal sinus
through foramen caecum

36. Erectile tissue
 Subepithelial venous
plexus
Seen on
 inferior turbinate
 posterior part of middle
turbinate
 Corresponding part of the
septum

37.  Nerve supply: maxillary division of trigeminal-
sensory supply to majority of nasal septum
Bulk of bony septum: naso palatine nerve
Ant superior: ant ethmoidal br of nasociliary
nerve
Smaller ant inferior: ant sup alveolar nerve
 Post inf septum also receives small supply from the
nerve to pterygoid canal and post inf nasal branch of
ant palatine nerves
 Olfactory epithelium covers the inf surface of
cribriform plate spreading on upper septum and
adjacent lateral wall over the medial surface of sup
concha

39.  Nerve firbers arising from olfactory receptors are
slim(0.2micr)& nonmylinated
 They are upto 20 bundles which traverse cribriform
plate to reach olfactory bulb,each bundle carry
dura&pia-arachnoid which may be sheared in head
injuries destroying olfaction n producing CSF leak.

40. LATERAL WALL
 Irregular
 Covered by ciliated columnar ep.
 Main area of drainage of sinus secretions.
Formed by
 Medial wall of maxilla
 Lateral mass of ethmoid & lacrimal bone
 Ascending process of maxilla
 Perpendicular plate of palatine bone
 Medial pterygoid process of sphenoid

41. LATERAL WALL
 3 scroll shaped horizontal elevations
 Superior
 Middle
 Inferior turbinate/concha
 Supreme(rare)
 3 meatuses
 Superior
 Middle
 inferior

42. Superior turbinate
 Part of ethmoid bone
 Medial surface is lined by olfactory epithelium
 Rarely a small ridge seen above superior turbinate –
“supreme turbinate”

43. Middle turbinate
 Part of ethmoidal bone
 It has a basal lamina which passes laterally to join
lamina papyracea
 Has an ascending limb which joins cribriform plate
 Posterior end points towards sphenopalatine foramen
 Covered by erectile tissue
 Pneumatization – concha bullosa
 Paradoxical middle turbinate

44. Middle turbinate, basal
lamella

45. INFERIOR TURBINATE
 Separate bone
 Irregular surface, perforated
 Has Maxillary process which articulates with inf.
Margin of Maxillary hiatus
 Also articulates with Ethmoid, Palatine, Lacrimal
bones completing the medial wall of NLD duct.
 Lined by respiratory epithelium.
 Subepithelium contains a rich cavernous venous
plexus.

47. LATERAL WALL
 Inferior meatus -- Lateral to IT
Largest meatus
Extends almost length of nasal cavity
highest at jn of ant.& middle 1/3
ranges from 1.6-2.3cm
NLD opens into it just ant.to highest
point
Not true valve – HASNER’s VALVE

49. MIDDLE MEATUS
 Most complex
 Lateral to MT.
 Forward continuation of MM- Atrium
 Curved ridge above atrium - agger nasi
 FS, MS, AES drains into it
 Opens through Maxillary hiatus bounded by

50. MIDDLE MEATUS
Inf – maxillary process of IT
Post – Perpendicular plate of Palatine bone
Sup – Uncinate, Bulla
Ant – Lacrimal
 Mucous membrane covering hiatus can be divided into
Anterior & Posterior fontanelle based on Uncinate process
 Accessory ostia are found in this fontanelle (4-5%)

52. UNCINATE PROCESS
 Cresentric or Boomrang shape
 Attachments :
Sup – May attach to LP, FE, MT
Ant – Maxillary process of IT
 When it attaches to LP, EI leads superiorly into a blind
pouch, TERMINAL RECESS

55. AGGAR NASI
 Crest on lateral wall ant.to attachment of MT
 Occassionally pneumatized
 Pneumatized portion may encroach upon NLD

56. HIATUS SEMILUNARIS
 2-dimensional space between UP and BE
 Can also be termed as Hiatus Semilunaris Inferioris

58. ETHMOIDAL INFUNDIBULUM
 3-dimensional funnel connecting natural maxillary
ostium to MM via Hiatus Semilunaris
 Bounded by – medially – UP
Laterally – LP
Anteriorly – blind recess where UP
meets LP
posteriorly – Ant.face of BE
Superiorly – varies with attachment of
UP

59. FRONTAL RECESS
 Found in most anterior superior portion of MM
 Hour glass shaped
 Bounded by medially – MT
laterally – LP
Superiorly – skull base
Inferiorly – depends upon attachment of
UP

61. BULLA ETHMOIDALIS
 Most consistent anterior Ethmoidal air cell
 Also called as TORUS LATERALIS (or) LATERAL BULGE
 Bounded by– Ant – Post.margin of HS & EI
Post – may fuse with basal lamella
Sup – may reach roof of etmoids forming
posterior wall of FR
 Some times a cleft is encountered btw post wall of bulla
&basal lamella of MT – retrobullar recess
 Cleft like space b/w bulla and skull base – suprabullar
recess.
 Together form semilunar space called “Sinus lateralis of
GRUNWALD”

63.  Anatomical variations:pneumatisation of MT
enlargement of EB
paradoxically bent MT
everted uncinate process
presence of haller cells
septal deflection

67. Superior meatus
 Defined by its relations with ST
 Post ethmoidal cells open into it.(by one or two
opening)
 A supreme turbinate is descrinible above the sup
meatus in 60-67% of sub
 SPHENOETHMOIDAL RECESS: a shallow
depression above, posterior & medial to ST & is the
location of ostium of sphenoid sinus.

68. OSTEOMEATAL COMPLEX
This is the area bounded by the middle
turbiante medially, the lamina
papyracea laterally, and the basal
lamella superiorly and posteriorly. The
inferior and anterior borders of the
osteomeatal complex are open.
This is in fact a narrow anatomical
region consisting of :
1.Multiple bony structures (Middle
turbinate, uncinate process, Bulla
ethmoidalis)
2.Air spaces (Frontal recess, ethmoidal
infundibulum, middle meatus)
3.Ostia of anterior ethmoidal, maxillary
and frontal sinuses.

69. Osteomeatal complex
 Defined as a microarchitectural drainage pathway for
anterior group of PNS.
 Consists of narrow cleft of ethmoidal influndibulum,
b/w UP & BE
 Cleft comprises of maxillary sinus ostium and frontal
recess.
 Anatomical and pathological abnormalities in this
region leads to persistent infection and disease within
major sinuses.

70. Blood supply of lateral wall
 External & Internal carotid
 Sphenopalatine art-majority of supply to turbinates &
meatus
 Greater palatine-lateral wall adjacent to palate
 Branch of Facial artery- anterior part
 Ethmoidal art br of IC- sup lateral wall
 VENOUS DRIANAGE: sphenopalatine vein via facial &
opthalmic vein.
 Intracranially via ethmoidal veins to veins on dura&
sup saggital sinus via foramen ceacum.

73. Nerve supply
 Olfaction –sup concha
 Ant ethmoidal nerve-ant superiorly
 Br of pterygopalatine ganglion & ant palatine nrv-
posteriorly
 Infra orbital nerve-anteriorly
 LYMPHATICS: sub mandibular---anteriorly
lateral pharyngeal
retro pharyngeal ---posteriorly
upper deep cervical

75. PARANASAL SINUSES

76. MAXILLARY SINUS
 Antrum of Highmore.
 largest of all paranasal
sinuses
 Pyramidal shaped ,
Lying just under
the cheek.
 Capacity of 15-30ml.

77. Anterior wall (anterolateral wall)–
covered by periosteum, soft tissue and skin of cheek.
lateral wall of the maxilla.
Its relatively thinner in the canine fossa & present lateral to canine
eminence
Caldwell Luc operation.
Infra orbital foramen- 1cm below the infraorbital margin
Roof –
floor of the orbit(infraorbital vessels and nerve).
Posterior wall –
temporal surface of maxilla.
Thin plate of bone related pterygopalatine fossa
PPF- 3rd part of IMA, vidian nerve, sphenopalatine ganglion
Floor – alveolar process and palatine process of the maxilla.
Medial wall (base of maxillary sinus)- lateral wall of the nasal cavity.
Laterally (apex of sinus) – zygomatic bone

79. OSTIUM OF MAXILLARY SINUS
 Opens in the
Posteroinferior end of
hiatus semilunaris.
 Close to roof of sinus.
 Unfavorable for
drainage of sinus.
 In children the floor lies
at or above the level of
the floor of the nasal
fossa.
 In adults it lies about
1.25cm below the floor of
the nasal fossa

80. SPHENOIDAL SINUS
 Lie within the body of
the sphenoid bone
 Below sella turcica
(extends between
dorsum sellae and post
clinoid processes)
 The average capacity is
7ml.
 Intersphenoid septum.
 Distance between
sphenoid ostium to ant.
Nasal spine is 7cms.

81. Superiorly
 Pituitary gland
 Optic chiasma
 Olfactory tract
 Frontal lobe of the brain.
Anteriorly
 Sphenopalatine foramen
 Sphenoidal crest
 Nasal cavity

82. Inferiorly
 Nasopharynx and choanae
 Vidian nerve is situated inferolaterally
Posteriorly
 Basilar artery
 Brain stem
Laterally
 Cavernous sinus and its contents( 3,4,5&6 CN)
 Internal carotid artery.

83. RELATIONS OF SPHENOIDAL SINUS

84. OPENING OF SPHENOID SINUS
Opens into the sphenoethmoidal recess above
the superior concha.
Ostium -Size (0.5-4mm)

85. ETHMOIDAL SINUS
⚫ They are anterior,
middle, and posterior.
⚫ They are contained
within the ethmoid bone,
between the nose and
the orbit.
⚫ Anterior & middle
drains into middle
nasal meatus
⚫ Posterior drain into
superior nasal
meatus

86.  Superior wall (roof) – Fovea ethmoidalis
 Laterally –lamina papyracea
 Posteriolaterally – sphenoid sinus.
PE cells may extend lateral to sphenoid sinus, where it is
related to the optic nerve- Onodi cells.
Medially – nasal cavity

87. FRONTAL SINUS
⚫ Second largest sinuses
◦ 2 – 2.5 cm
⚫ Rarely symmetrical
⚫ Contained within the
frontal bone .
⚫ Separated from each
other by a bony septum.
⚫ Each sinus is roughly
triangular
⚫ Extending upward above
the medial end of the
eyebrow and backward
into the medial part of
the roof of the orbit.

88. FRONTONASAL DUCT
Opens into the middle meatus
The average capacity is about 7 ml in the adult.
True frontonasal duct only in 15% of people.
FS is absent at birth.

89.  Position: it is situated b/w outer and inner table of
frontal bone
 Floor : formed by orbital roof. Relatively thin
 Medially : interfrontal septum
 Posteriorly: ACF
 Anteriorly : periosteum and skin of forehead.

90. DRAINAGE OF SINUSES