paranasal sinuses anatomy

2. Prepared By:
Dr.Priya

3. CONTENTS
• INTRODUCTION
• DEVELOPMENT
• FUNCTIONS
• MAXILLARY SINUSES
• FRONTAL SINUSES
• ETHMOIDAL SINUSES
• SPHENOIDAL SINUSES
• APPLIED ANATOMY

4. INTRODUCTION
• Air containing bony spaces around the nasal cavity
• Each sinus named after the bone it resides in
• Arranged in pairs
• Frontal, Ethmoidal, Maxillary, Sphenoidal

5. PARANASAL SINUSES
 Anterior group - maxillary,
frontal, anterior ethmoidal
 Posterior group – sphenoid,
posterior ethmoidal

6. LATERAL VIEWFRONTAL VIEW

7.  Development of sinus begins as
invagination of mucus membrane
in lateral wall of middle meatus
when nasal epithelium invades
maxillary mesenchyme
(Kitamura, 1989)
DEVELOPMENT

8. 3 conchae & meatus
Superior & inferior
- Shallow depression
Middle
- Expansion in lateral wall of nose

9.  Maxillary sinus– biphasic growth
at birth (filled with fluid)
age of 0-3 years (horizontal growth)
age of 6-12 years(perpendicular
growth down to teeth)

10.  Ethmoidal sinus
At birth (filled with fluid)
 Develop during puberty and develops slowly till 17-18 yrs
Punematization begins 4th year of childhood ,
 Completed by 17th year of life

11.  Sphenoidal sinus
 undeveloped and non aerated at birth
 Aeration : 3 yrs
• Progresses posteriorly

12. ☐ Frontal sinus
• Last sinus to develop
• Remain as small blind sac within
frontal bone till 2 years of age
• Pneumatization : 2 to 9 years

13. PHYSIOLOGY
• Sinuses are lined by respiratory
epithelium
• Length 1-2 mm
• Act as “Conveyer Belt”
• Entrap and carry organisms
and dust particles
• Increase surface area of cell
prevent drying of surface

14. Histopathology

16. FUNCTIONS OF SINUSES
 Reduced Skull weight
 Impart resonance to voice
 Mucus production and storage
 Humidify and warm inhaled air
 Define facial contour
 Immuno defensive action

17.  Conserve heat from nasal fossa
 Moisturize air
 Filters debris
 Dampen pressure differential during inspiration
 Serves as accessory olfactory organ
References :Chaurasia BD. Human anatomy Head and Neck.
Fourth edition. India: Cbs Publishers and distributors; 2004.

18. RADIOGRAPHIC APPEARANCE

21. MAXILLARY SINUS
• Also known as antrum of
Highmore
• Pneumatic space that is situated
inside the body of the maxilla and
communicates with middle meatus
and the nasal vestibule

22. • Largest of the paranasal sinuses
• Capacity: 15-30 ml
• Paired and symmetric
• Pyramidal in shape
• Avearge measurement :
Vertical Height : 3.5cm
Transverse Width : 2.5cm
Antero-posterior Depth: 3.5cm

23. BOUNDARIES
 Base : Nasal surface of the body of maxilla
 Apex : Projects laterally into zygomatic process
of maxilla and it may extend till zygomatic
bone when sinus is very large
 Roof : Orbital surface of maxilla

24. Floor
 Formed by junction of anterior
sinus and lateral nasal wall
 1-1.2 cm below nasal floor
 Closely approximated to 2nd PM,
1st Molar, 2nd Molar

25. WALLS
ANTERIOR POSTERIOR
MEDIAL LATERAL

26. Anterior wall:
• corresponds to the cheek
of face
• Thinnest wall of sinus
• Canine fossa

27.  Medial wall: lies between the sinus and
nasal cavity
 Posterior wall: related to pterygopalatine
and infra temporal fossa
 Lateral wall : related to zygoma and
cheek

28. ARTERIAL SUPPLY
INFRA-ORBITALARTERY MAXILLARY ARTERY
POSTERIOR
SUPERIOR
ALVEOLAR
ARTERY

29. NERVE SUPPLY
 Branches from anterior,
middle and superior
alveolar nerve
 Greater palatine nerve

30.  VENOUS DRAINAGE
 Facial vein
 Anteriorly: spheno-palatine vein
 Posteriorly: pterygoid vein plexus
 LYMPHATIC DRAINAGE
 submandibular lymph node
 Deep cervical lymph node

31. RADIOGRAPHIC APPEARANCE
 Appears as a thin, delicate
radiopaque line
 It extends from the distal
aspect of canine to the posterior
wall of tuberosity

32.  In response to the loss
of posterior teeth the
sinus may expand
further into alveolar
bone

33. FRONTAL SINUS
 Location : Frontal bone
 Usually asymmetrical
 Shape : Triangular
 Development : Age of 6-7yr
 Average Measurement
Vertical (H) : 3 cm
Transverse (W) : 2.5cm
Antero Posterior (D) : 1.8 cm
FRONTAL SINUSES

34.  BOUNDARIES
 Extending upward above the
medial end of eyebrow
 Backward : medial part of the
roof of the orbit
 Floor: upper part of orbit
 Posterior wall: anterior cranial
fossa

35. NEUROVASCULAR SUPPLY
 Nerve supply- supra orbital nerve
 Artery supply - supra orbital artery
Lymphatic drainage - submandibular lypmh
nodes

36. FRONTAL SINUSES

37. ETHMOIDAL SINUS
Location : Ethmoidal bone
Between the nose and the orbit
Number : 3 -18 ethmoid cells
Development : After 2nd year

38. BOUNDARIES
• Above:
orbital plate of frontal bone
• Below :
orbital process of palatine bone
• Anteriorly : lacrimal bone
• Lateral wall : Lamina Papyracea

39. ganglion
Olfactory branches

40. NEUROVASCULAR SUPPLY
ARTERIAL SUPPLY :
Anterior and posterior
ethmoidal branches of
opthalmic artery
NERVE SUPPLY :
Posterior ethmoidal
nerves and vessels
The orbital branches of
pterygo palatine
ganglion

41. • LYMPHATIC DRAINAGE:
Anterior and Middle groups
Sub-mandibular Lymph Nodes
Posterior group
Retro pharyngeal lypmh nodes

42. RADIOLOGICAL APPEARANCE

43. SPHENOIDAL SINUS
• Assymetric
• Situated in sphenoid bone;
at junction of anterior and
middle cranial fossa
• Fourth week IUL
• Capacity : 7ml

44. • varies in size
• Two in number
• Open into sphenoethmoidal recess, which is located
above superior conchae
• Drains into superior meatus

45. BOUNDARIES
• Lateral
Cavernous sinus and
Internal carotid artery

46. • Superiorly :
Pitutary gland
 Floor :
Vidians nerve

47. NEUROVASCULAR SUPPLY
• Nerve supply : posterior ethmoidal nerve and orbital branch of
pterygopalatine ganglion
• Artery supply : posterior ethmoidal vessels
• Lymphatic drainage : RetroPharyngeal nodes

48. SPHENOIDAL SINUS

49. DRAINAGE

50. DRAINAGE

51. MAXILLARY FRONTAL
ETHMOIDAL SPHENOIDAL
APPLIED
ANATOMY

52. MAXILLARY SINUS
• The anterior and infra-temporal wall of maxillary sinus are
very thin
 Tumors developing within the sinus can readily erode them
and present as swelling in the cheek
 Tumors may penetrate the floor of sinus and present as lump in
the palate

53. Infection begins
Ostium wall swells
Drainage pathway
closes
Sinusitis

54.  Inflammation by
 Infection
 Allergy
 Foreign body
Mucositis

55. Direct communication
maxillary antrum and
oral cavity
Oro-antrum fistula

56. AETIOLOGY
Extraction
Excessive Force
Chronic infection
Infected : implant
dentures
Extensive trauma
:face
Destruction:
sinus floor:
periapical lesions
Perforation:
Instruments
Surgery
:cyst;sinus cavity
Malignant
diseases:
granuloma

57. SPHENOIDAL SINUS
• Infection of sphenoid sinus
may involve the optic nerve
• Mucous retention pseudocyst
ETHMOIDAL SINUS
Lesions of olfactory nerves due to fracture of cribiform plate may
result in loss of the sense of smell

58. REFERENCES
• Chaurasia BD. Human anatomy Head and Neck. Second edition.
India: Jaypee Brothers; 2004.
• Datta AK. Essentials of Human anatomy Head and Neck. Third
edition. India : Current Publishers ;2006.
• Malik NA. Oral and Maxillofacial surgery. Second edition. India:
Jaypee Brothers; 2008.
• Ghom AG. Oral Medicine. Second edition. India : Jaypee Brothers;
2010.
• Internet