1. EMBRYOLOGICAL DEVELOPMENT & ANATOMY OF NOSE
Presenter – Dr Pulkit Agarwal
Moderator – Dr G.S.Renukananda

2. EMBRYOLOGY 4th to 8th week from 5 Swellings (Ectoderm)
Ectodermal thickenings(5th week)
1st Arch

3. 6th week : ectoderm from Nasal placode invaginates to form oval nasal pits

4. 12.5 mm Enbryo stage : Maxillary prominence grows medially

5. Nasal pits separate from stomodeum

6. Intermaxillary process (fusion of medial nasal process) central tissues pushed up to form nasal prominence

7. By 7th week invaginates to form nasolacrimal duct
Canalisation may not complete till after birth
Globular process forms the philtrum (lateral angles of medial nasal process)

8. Nasal Septum Development – 13.5 mm embryo stage (6th week)
Fusion of maxillary to frontonasal process.
Midline ridge from posterior end of frontonasal process forms septum
6th week
15mm stage

9. Nasal pits deepen and coalesce (end of 6th week)

10. Primitive Choanae formed at 7th week

11. Primitive nasal septum is completely Cartilagenous
2 centres
Groove on which septal catilage sits

12. Palatine shelf – Medial extensions of maxillary process
Lateral nasal processes – nasal alae and lateral nasal wall
Hard palate formed by around 8th and 9th week
Palatine shelf – Medial extensions of maxillary process

14. Fuses with septum forming 2 passages which opens into defintive choanae

15. Paraseptal Jacobsons cartilage invagination of ectoderm leads to Vomeronasal Organ

16. Disappears leaving a blind tubular pouch 2 – 6mm long

17. Jacobsons cartilage involutes leaving small cartilagenous bulge

18. VNO / Jacobsons organ is first stage of the accessory olfactory system, and contains sensory neurons that detect chemical stimuli mainly used to detect pheromones found in many animals

20. Processes Structures Formed
Frontonasal
Forehead, Bridge of nose, medial and lateral nasal prominences
Maxillary
Cheeks, Lateral portion of upper lip
Medial Nasal
Philtrum of upper lip, Crest and tip of nose
Lateral Nasal
Alae of nose, lateral nasal wall
Mandibular
Lower lip and jaw

22. ANATOMY External Nose Nasal Cavity Nasal Septum Lateral Wall
Anatomical Variations

23. External nose :

24. Skin & Vestibule : Skin : Vestibule :
Thickness of skin and soft tissue varies.
Over dorsum and side – thin and loose
Over tip & alar region – thick and adherent
Vestibule :
Anteriormost part of nasal cavity lined by stratified squamous keratined epithelium.
Demarcated by limen nasi
Lined by coarse vibrissae, glands

25. Blood supply ICA  Ophthalmic Artery
Vth  Ophthalmic nerve  Anterior ethmoidal External nasal nerve (Dorsum, tip)
Vestibule of nose
Maxillary artery
ECA

26. VENOUS DRAINAGE LYMPHATIC DRAINAGE Corresponds to arteriovenous units.
Frontomedian area drains into the facial vein
Orbitopalpebral area – ophthalmic vein (cavernous sinus communication)
LYMPHATIC DRAINAGE
Submandibular and submental nodes and sometimes buccal nodes intervene

27. Nerve supply Trigeminal Nerve Ophthalmic Branch Maxillary Branch
Infraorbital nerve
Anterior Ethmoidal
Nasociliary
External Nasal
Infratrochlear

28. Vestigial importance

29. Depresses Septum
Tip of nose
Expandes nares during forced inspiration

30. Transverse – Pyriform aperture to Dorsum of nose & Contracts nasal aperture
Alar – beneath nasomaxillary suture line via short thin tendon to skin of nasal alae Contraction causes shortening and dilation of Nostril

31. Continuation of Frontalis
Shortens nose on contraction and also movements in region of eyebrows hence aka Depressor Glabellae

32. Frontal process of maxilla
Blends with lateral crus of lower lateral cartilages & pulls it superiorly
Also pulls lips superiorly helping in dilation

33. framework Bony : Cartilagenous: Nasal Bone
Nasal process of frontal Bone
Frontal process of maxilla
Cartilagenous:
Paired upper lateral cartilages
Septal Cartilage
Paired lower lateral cartilage / Greater alar cartilage
Minor accessory alar cartilages

34. Supported by Nasal Spine and perp. Plate of ethmoid
Nasolacrimal Suture
Supported by Nasal Spine and perp. Plate of ethmoid

35. Upto 15mm
Nasal bones are supporetd by perp plate of ethmoid and nasal spine both of which groove the bone

36. Overlapped by Nasal bone, Maxilla, Alar cartilage
(Fibrous Cartilage)
Limen Nasi
(Intercartilagenous Incisions)
Hyaline cartilages which may be ossified & prevent collapse of vestibule

37. Overlapped by Nasal bone, Maxilla, Alar cartilage
(Fibrous Cartilage)
Limen Nasi
(Intercartilagenous Incisions)
Medially continuous with septal cartilage which is bifid in this region

38. Medial Crus
Lateral Crus
Medial is loosely attached in midline anterior to Quadrangular Cartilage & contributes to Columella (area from tip to philtrum)

39. Lower margin of lateral ascends away from margin of Nostril
Medial Crus
Lateral Crus
Lower margin of lateral ascends away from margin of Nostril

40. 3 – 4 sesamoid cartilages present
Medial Crus
Lateral Crus
3 – 4 sesamoid cartilages present

41. Nasal Cavity
Extension
Vertical Extent
(Broader)

42. Each half has a floor, roof lateral and medial wall.
HORIZONTAL PROCESS
Each half has a floor, roof lateral and medial wall.
Floor – concave, Ant 3/4th – Palatine process of maxilla and posterior 1/4th by horizontal process of palatine bone
12mm behind ant end, mucous memb dips overlying incisive canal
Contains terminal branches of Nasopalatine nerve, greater palatine artery & short mucosal stensons canal

43. Lateral Wall = Lateral Wall of Nose
Roof :
Frontonasal
Ethmoidal
Sphenoidal
Highest, Cribriform plate of ethmoid which is horizontal
Resp epithelium continuous with PNS, NLD & nasopharynx
Olfactory epithelium
Medial Wall = Septum
Lateral Wall = Lateral Wall of Nose

44. Nasal septum Bones – Perpendicular plate of ethmoid Vomer
Two bony crests of the
maxilla and palatine
Rostrum of sphenoid
Nasal spine of frontal bone
Cartilages –
Quadrilateral cartilage
Upper and lower lateral cartilages contribution
Vomeronasal Cartilage
Membranous septum

45. QUADRANGULAR CARTILAGE
3 – 4 mm centrally and 4 – 8 mm anteroinferiorly (footplate)
Above dome of lower lateral cartilages, upper angle expanded forming anterior septal angle
Perp Plate of ethmoid
forms superior and anterior bony septum
Above is cribriform plate and cristae galli
Grooves nasal bones
Post free edge of vomer
vomer
Posterior and inferior septum
With 2 alae articulates with rostrum of sphenoid, forms vomerovaginal canals which transmit pharyngeal branch of maxillary artery
Inferiorly – with both crests
Anterior – perp plate & septal cartilage

46. Blood Supply
Posteroinferior septum and anteroinferior face of sphenoid sinus
& posterior halves of middle & inf turbinates
b/o maxillary artery b/o ECA

47. Blood Supply
Supplies anteroinferior portion entering the nasal cavity via incisive canal
b/o maxillary artery b/o ECA

48. Blood Supply
Supplies anteroinferior portion entering the nasal cavity via incisive canal
b/o Facial artery b/o ECA

49. Blood Supply
b/o ICA

50. Sinusoidal system in nasal submucosa under autonomic control described well with turbinates but also seen in septum adjascent to inferior turbinate and most anterior part of septum
Related to control of airflow in nasal cavity
In 2/3rd seen in posterior septum
Nerve supply
Maxillary nerve (V2) supplies majority of septum
Nasopalatine nerve, posterosuperior nasal branch of maxillary nerve supplies bulk of bony septum entering via sphenopalatine foramen.
Anterosuperior – anterior ethmoidal branch of nasocilairy nerve (V1 branch)
Small Anteroinferior area supplied by anterior superior alveolar nerve

51. Anterior superior alveolar nerve
b/o pterygopalatine ganglion and carries both sensory and parasympathetic fibres
& also Vidian nerve

52. Nerve supply of septum

53. Olfactory, respiratory and stratified squamous keratinised epithelium
Sensory nerves accompanied by postganglionic sympathetic nerves to blood vessels and postganglionic parasympathetic secretomotor fibres pass to glands with the branches from the pterygopalatine ganglion
Olfactory, respiratory and stratified squamous keratinised epithelium
Surface area increased by cilia on respiratory cells
Nerve fibres from olfactory receptors are slim and bundled together in sets of 20 to pass through cribriform plate
Carries dura, pia along
Shearing may lead to CSF leak or destruction of olfaction
LYMPHATIC DRAINAGE
Anteriorly – Submandibular LN
Posteriorly – Retromandibular & deep cervical LN

54. Lateral wall
Roof of posterior choanae
1 cm
Straighter

55. Atrium – Structureless area
Shows bulge anterior to middle turbinate formed by agger nasi cells
Ridge from agger nasi to apex of superior border of inferior turbinate which overlies NLD
3 scrolls of turbinates. Occasionally supreme turbinate.
Sphenoethmoidal recess above superior turbinate which forms niche between posterior ethmoidal cells and sphenoidal cells
Fossa of rosenmuller forms a deep cleft behind torus tubaris
Attachments of middle turbinate :
Anterior 1/3rd – cribriform plate at jnct in saggital plane also takes a small anterior attachment to frontonasal process(maxilla)
Middle 1/3rd – lamina papyracea in coronal plane (ground lamellae)
Posterior 1/3rd – to lamina papyracea and the perpendicular plate of the palatine bone extending upto the roof of posterior choanae

57. Behind middle turbinate, most anteriorly – Uncinate process
Separated from well pneumatized ant ethmoidal cell (bulla) by hiatus semilunaris inferioris.
Hiatus semilunaris leads into infundibulum
Osteomeatal Complex
As per Naumann :
Osteomeatal complex is complex microarchitectural pathway in ethmoid labyrinth that drains anterior group of paranasal sinuses and consists of frontal recess, ethmoid infundibulum, hiatus semilunaris, uncinate process, bulla ethmoidalis and middle meatus

59. Uncinate process – sickle shaped, Horizontal and vertical parts & intermediate transitional part
Retrobullar recess – Between bullae and ground lamellae
Suprabullar recesss – If bulla doesn’t extend till skull base
Together form space above and behind the bulla called Sinus Lateralis of grunwald which opens in middle meatus via Hiatus semilunaris superioris
Boundaries :
Roof : Ethmoid fovea
Floor : Ethmoid bulla
Posteriorly : Ground lamella
Anteriorly : Frontal recess
Laterally : Lamina papyracea
Medially : Middle turbinate
Infundibulum leads into the frontal recess

61. Frontal Recess :
Boundries
Anteriorly : Agger Nasi cells (a part of Frontal recess)
Posteriorly : Bulla Ethmiodalis (a suprabullar recess will open in posterior wall of frontal recess)
Laterally : Lamina Papyracea
Medially : Middle turbinate
Superiorly : Opens via the frontal ostium into the frontal sinus
Frontal sinus opening is funnel shaped (FI) in posteromedial floor of sinus. Hour glass config.
Upper end of Uncinate lies in frontal recess.
Large no of anatomical variations but 80% attached to lamina papyracea in form of dome
Dome like attachement of uncinate in frontal recess described by Stammberger – eggshell in inverted cup

63. Recess enclosed within this dome is called recessus terminalis
In this case frontal sinus opens medial to uncinate process
Well hidden by the uncinate process lies an opening of the maxillary sinus
Normal ostium – 3D, Ovoid and tunnel like
Accessory osteum – 2D, Circular
Relations of maxillary ostium are : Inferiorly is the inferior turbinate, 1 to 2 mm superiorly is the lamina papyracea and the orbit, posteriorly is the posterior fontanelle, 0.5 cm anteriorly lies the nasolacrimal duct
Anterior fontenelle – AI to uncinate
Posterior fontenelle – PS to uncinate
Both are just double layer of mucous membrane without underlying bone, thus if memb deficient can lead to accessory ostia

66. Bulla may drain into the middle meatus/hiatus semilunaris/ sinus lateralis
Frontal sinus drains into frontal recess medial or lateral to uncinate process depending on the mode of attachment of the uncinate process or suprabullar recess if present
Maxillary sinus – always in infudibulum
Sphenoid sinus – Sphenoethmoidal recess

67. Meatal Drainage Inferior meatus : NLD (Hasners valve) Middle meatus :
Frontal
Anterior ethmoidal
Maxillary
Superior meatus :
Posterior ethmoidal
Sphenoethmoidal recess :
Sphenoid

69. Arteries Of lateral and medial wall of Nose

70. Anterior ethmoidal & Posterior Ethmoidal arteries
Artery
Branch of
Supplies
Anterior ethmoidal & Posterior Ethmoidal arteries
Ophthalmic artery(ICA)
Ethmoid and frontal sinuses, roof of the nose, upper part of lateral wall and septum
Sphenopalatine artery
Maxillary artery 3rd part (ECA)
Mucous membrane, superior and middle meatus, conchae and septum
Greater palatine artery
Maxillary artery (ECA)
Posterior part of lateral nasal wall (also anteroinferior end of septum)
Superior Labial
Facial artery (ECA)
Region of vestibule of nose

71. Pharyngeal branch of maxillary sinus supplies sphenoid sinus
Infraorbital artery, anterior and posterior superior alveolar arteries b/o Maxillary artery supply Maxillary sinus
Pharyngeal branch of maxillary sinus supplies sphenoid sinus
Nerve supply :

72. (V1)
(V2)

73. Anatomical Variations
DNS –
AP deviations best seen in axial scans
Spurs at vomerocartilagenous junction – Coronal scans
Near OMC may lead to impaired drainage of sinuses
Concha bullosa or HIT on roomy side may compromise OMC
Septum may be pneumatised
Agger Nasi cells –
Can be hypoplastic or prominent leading to displacement of anterior attachment of middle turbinate posterosuperiorly
Uncinate process –
Hypoplastic / laterally bent – Infundibulum narrow space difficult to enter
Medially bent so much so to resemble anterior wall of bulla, or may be curled upon itself to appear like a duplicated middle turbinate

74. Variations attachment of Uncinate –
Skull base
Middle turbinate
Insertion of middle turbinate
May lie free in the middle meatus
May be pneumatised
Uncinate if attached to skull base, frontal sinus drains into infundibulum and therefore diseases from the frontal sinus can spread directly to the maxillary sinus and vice versa
Middle turbinate :
Pneumatised – concha bullosa (either from agger nasi/frontal reces or from anterior ethmoidal cells)
Concha may obstruct airway, affect drainage of secretions and lead to chronic infections of sinuses
Occasionally middle turbinate may pneumatise the vertical lamella of the middle turbinate to produce what is called the intralamellar cell of Grunwald

75. May take a paradoxical sharp bend laterally, often bilaterally leading to blockade of infundibulum
Can sometimes curl upon itself to produce a concavity within it called turbinate sinus
Ethmoidal bulla :
Hypoplastic or non pneumatised hillock
May be excessively pneumatised abutting against uncinate process anteriorly or the middle turbinate compromising infundibulum or middle meatus respectively
The sinus lateralis may extend laterally to pneumatise the roof of the orbit thus forming the supraorbital ethmoid cell. This cell is seen in coronal CT scan at the level of the bulla behind the frontal sinus
Ethmoid Air Cells :
The anterior and posterior ethmoid air cells may pneumatise surrounding bones like lacrimal bone, maxilla, frontal bone, sphenoid to produce varying patterns of pneumatisation