The document summarizes key information about the maxillary sinus, including its development, anatomy, blood supply, drainage, and clinical importance. It begins with a brief overview of paranasal sinuses and then focuses on the maxillary sinus. The maxillary sinus develops from the maxillary process by 12 weeks gestation and increases in size throughout childhood and adulthood. It has multiple walls that form its boundaries and drains into the middle meatus through the maxillary ostium. Issues like sinusitis, dental infections, and trauma can involve the maxillary sinus.

2. MAXILLARY SINUS
-Development ,Anatomy & Applied
aspect
Seminar by –Zareesh Akhtar
1ST YEAR MDS IN OMR

3. Contents
• Introduction
• Development
• Anatomy
• Microscopic feature
• Function
• Developmental anomalies
• Applied anatomy
• References

4. Introduction
• Paranasal sinuses (PNS) are air containing bony spaces around the nasal
cavity.
• These spaces communicate with the nasal airway and form the various
boundaries of nasal cavity and are named according to the bones in which
they are located
• There are 4 pairs of paranasal sinuses present bilaterally as follows
• 1-MAXILLARY AIR SINUS
• 2-FRONTAL AIR SINUS
• 3-ETHMOIDAL AIR SINUS
• 4-SPHENOIDAL AIR SINUS

5. Definition
‘‘ Maxillary sinus is the pneumatic space
that is lodged inside the body of the
maxilla and that communicates with the
environment by way of the middle nasal
meatus and the nasal vestibule ’’
-ref Orban’s Oral histology

6. History and etymology
• The maxillary sinus was first discovered and
illustrated by leonardo da vinci but earliest
attribution was given to nathaneil highmore
• The antrum highmorianum was first described in
detail by Nathaniel Highmore (1613-1685), a
british physician and anatomist
Nathaniel Highmore (1613-1685),

7. Development
• Maxillary sinus is the first of the PNS to develop
• 4th week of I.U life –dorsal portion of 1st pharyngeal arch forms the
maxillary process ,which extend forward and beneath the developing
eye to give rise to maxilla
• The development of the maxillary sinus follows a number of
morphogenic event in the differentiation of nasal cavity

9. Horizontal shift of the palatal shelves occur
Nasal septum separates the secondary oral cavity
from the 2 nasal chambers
Influences further expansion of the lateral nasal
wall and 3 wall begin to fold
Giving rise to 3 conchae and meatuses

11. • Superior & inferior meatus remain as a
shallow depression along the lateral
nasal wall for first half of I.U life
• Middle meatus expands into lateral
nasal wall in an inferior direction
occupying more of the maxillary body

12. • Development of sinus start at 12 week as an evagination of the mucous
membrane in the lateral wall of the middle meatus.
• This occurs when the nasal epithelium invades the maxillary
mesenchyme

13. • In the developmental process of
maxillary sinus
• It is –
• Tubular at birth
• Ovoid in child hood
• Pyramidal in adulthood

14. Dimension of sinus
• 0-3 years size is approx. 7mm *4mm,volume is 6-8ml
• 3-4year there is increase in width of sinus and facial growth
• 7-9 years size is approx. 27mm*18mm*17mm,growth
corresponds to eruption of permanent teeth
• 9-15yrs antral floor is at same level with nasal floor

15. • Then around 12-15yrs Floor sinus shift 12.5mm below nasal floor
• Size is approx. 32mm *33mm*25mm ,volume is 15-20ml
• In geriatric age there is resorption of ridge with pneumatization
leaving a thin layer of cortical bone between the nasal and oral
mucosa.

16. Anatomy
• The pyramid-shaped maxillary
sinus previously known
as antrum of Highmore
• largest of the paranasal sinuses, Found in
the body of the maxilla

17. • Described as a pyramid, the
maxillary sinuses have
• a base on the lateral border of the
nose, with
• the apex pointing towards the
zygomatic process of the maxilla.
• The floor is formed by the alveolar
process of the maxilla.
• The roof is the orbital floor. The
posterior wall forms the anterior
border of the pterygopalatine fossa.

18. Roof of the antrum
• Formed by floor of the
orbit and is transverse by
the infraorbital nerves
• It is flat and slopes
slightly anteriorly and
laterally

19. Floor of sinus
• It is curved rather than
being flat due to alveolar
process of maxilla
• Floor of sinus lies about
1cm below the level of
the floor of nose

20. Anterior wall of sinus
• Formed by the facial surface of
the maxilla
• Canine fossa is an important
structure present in this wall

21. Posterior wall of sinus
• Formed by spheno -
maxilary wall
• A thin plate of bone
separates the antral cavity
from the infratemporal
fossa

22. Medial wall of sinus
• Bound by the nasal cavity
• The opening of the sinus is
closer to the roof and at a
higher level than the floor
,which drains via the
maxillary ostium into
the infundibulum, then
through hiatus semilunaris int
o the middle meatus

23. Lateral wall of sinus
• It is related to zygoma
and cheeks

24. Ostium
• The medial wall is composed primarily
of cartilage.
• The ostia for drainage are located high on
the medial wall and open into
the semilunar hiatus of the lateral nasal
cavity.
• Because of the position of the ostia,
gravity cannot drain the maxillary sinus
contents when the head is erect .
• The ostium of the maxillary sinus is high
up on the medial wall and on average is
2.4 mm in diameter; with a mean volume
of about 10 ml.

25. Arterial supply
• Small arteries from the facial,
maxillary, infraorbital and
greater palatine arteries pierce
the bony walls of the
maxillary sinus.

26. Venous drainage
• Venous drainage anteriorly is via
the sphenopalatine vein and posteriorly via
the pterygoid venous plexus and the facial vein.
• Infection from the maxillary sinus may spread
to involved cavernous sinus via any of its
draining veins as the pterygoid plexus
communicates with the cavernous sinus by
emissary vein

27. Lymphatic drainage
• Lymph from the maxillary sinus drains
• to the submandibular group of lymph nodes
via the infraorbital foramen.
• Deep cervical lymph nodes
• Retro pharyngeal lymph nodes

28. Nerve supply
• Superior alveolar nerves
• Posterior superior alveolar nerves: dental
branches pierce the bone to supply the sinus
mucosa
• Middle superior alveolar nerves: supply the
pre-molar teeth and overlying mucosa of the
sinus
• Anterior superior alveolar nerves: supplies
canine and incisors and anterior wall of the
sinus

29. •Greater palatine nerve
• Minute branches from this nerve
supply the medial wall of the sinus
•Infraorbital nerve
• Perforating branches supply the
roof of the sinus

30. Microscopic feature
• The sinus is lined with mucoperiosteum, with
cilia that beat toward the ostia.
• This membranous lining is also referred to as
the schneiderian membrane, which
is histologically a bilaminar membrane
• An epithelial layer resting on basement
membrane with pseudostratified ciliated
columnar epithelial cells on the internal (or
cavernous) side and
• Subepithelial connective tissue layer.
• Periosteum on the osseous side.

31. Functions
• Impart resonance to the voice
• Increase the surface area and lightens the skull
• Moisten and warm the inspired air
• Mucus production and storage
• Limited extent of facial injury from trauma
• Provides thermal insulation to important tissues
• Serve as accessory olfactory organ

32. Developmental anomalies
• Agenesis –complete absence of MX sinus
• Aplasia / hypoplasia –seen associated with cleft palate, choanal
atresia, high palate, septal deformity, mandibular dystosis
,malformation of external nose
• Supernumery –two completely separated sinus on same side

33. Developmental anomalies
• Crouzon syndrome -early synostosis [fusion] of sutures
produce hypoplasia of the maxilla and therefore the maxillary
sinus together with high arched palate
• Treacher collins syndrome –Association with grossly and
symmetrically underdeveloped maxillary sinus and malar
bones.
• Binder syndrome – hypoplasia of middle 3rd of face with
smaller maxillary length and maxillary sinus hypoplasia.

34. Clinical Importance
• Dental infection –infection from maxillary premolar and molar can
easily communicate and infect the maxillary sinus.
• Oroantral communication –traumatic extraction of maxillary teeth.
• Root pieces- root pieces of maxillary teeth may sometime be
accidentally forced into the maxillary sinus.
• Maxillary sinusitis –because of the thickened and inflamed sinus
lining compresses the nerve supply of MX posterior teeth causing
tenderness of the maxillary teeth.

35. • The infraorbital and superior alveolar vessels are frequently ruptured
in maxillary fracture causing the hematoma formation in the antrum.
• Maxillary sinus is most commonly involved .it may be infected from
the nose or from caries , foreign dental material.drainage of the sinus
is difficult because it’s ostium lies at a higher level than it’s floor
• Hence sinus is drained surgically by making an artificial opening near
the floor by following two ways

36. • 1-Antrum puncture can be done
by breaking the lateral wall of the
inferior meatus and pushing in
the fluid and letting it drain
through the natural orifice with
the head in dependent position

37. • 2-An opening can be made at the canine
fossa through the vestibule of the mouth
,deep to the upper lip Caldwell –luc
operation

38. References
• B D chaurasia human anatomy
• Orban’s oral histology and embryology
• Textbook of oral medicine ,anil ghoms
• The location of maxillary sinus ostiu and its clinical application Indian
J Otolaryngel head and neck surg October –December 2010,62(4)335-
337
• Inderbeir singh textbook of embryology