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Paranasal air sinus
- 1. PARANASAL AIR SINUS Dr. Payal Dash 1ST year post graduate trainee Department of public health dentistry 1
- 2. CONTENTS • Introduction • Embryology • Growth and development • Histology • Functions • Evaluation of sinus • Maxillary air sinus • Frontal air sinus • Ethmoidal air sinus • Sphenoidal air sinus • Applied anatomy • Conclusion • References 2
- 3. INTRODUCTION • Paranasal sinuses are air filled spaces in certain skull bones. • Embryologically developed as diverticula of mucous membrane of the nose. • Bones containing air sinuses are called pneumatic bones. • Classified as – Anterior group Maxillary ,frontal ,anterior ethmoidal air sinuses Posterior group Posterior ethmoidal air sinuses, sphenoidal 3
- 4. EMBRYOLOGY • Begins at 3rd month in-utero • Outpouchings of superior and middle nasal meatus • Two primary process- primary pneumatisation secondary pneumatisation 4 SINUS PRIMARY PNEUMATISATION SECONDARY PNEUMATISATION MAXILLARY 10 weeks I.U. 5th month I.U. SPHENOIDAL 4th month I.U. 6-7 years ETHMOIDAL 4th month I.U. 2 years FRONTAL 4th month I.U. 6 months
- 5. GROWTH AND DEVELOPMENT 5 SINUS STATUS AT BIRTH GROWTH FIRST RADIOLOGIC EVIDENCE MAXILLARY Present Volume : 6- 8 ml Rapid growth from birth to 3 years.Adult size-15 years 4-5 months after birth ETHMOID Present Anterior group-5*2*2mm Posterior group-5*4*2mm Adult size by 12 years 1 year FRONTAL Not present Invades frontal bone at 4 years and size increases till teens 6 year SPHENOID Not present Sella turcica- 7 years Dorsum sellae-late teens Basisphenoid- adult age Adult 15 years 4 year Source- Diseases of ear ,nose and throat and head and neck surgery 6th edition- PL Dhingra ,Shruti Dhingra
- 6. HISTOLOGY • Microscopically 3 layers • Epithelial layer • Basal lamina • Subepithelial layer including periosteum • They are lined by pseudostratified columnar epithelium studded with mucus and serous glands 6
- 7. FUNCTIONS • Air conditioning of inspired air • Lighten the skull bones • Resonance for voice • Protection of orbit • Provide extended surface for olfaction • Provide local immunologic defence • Act as buffers against trauma 7
- 8. EVALUATION OF SINUS • Clinical examination- Inspection Palpation Percussion Transillumination 8 Palpation Transillumination
- 9. • Radiographs- Periapical, occlusal,lateral (intra-oral) Panoramic ,Water’s view, submentovertex (extra-oral) 9
- 10. 10 • CT scan and MRI • Endoscopy
- 11. MAXILLARY AIR SINUS • Also know as Antrum of highmore (1651) • Largest of all • Pyramidal in shape • Capacity-15cc (average) 11 Maxillary sinuses
- 12. BOUNDARIES • APEX- zygomatic process of maxilla • BASE- lateral wall of nasal cavity • ROOF- floor of orbit • FLOOR- alveolar process of maxilla situated 1.25cm below the level of nasal floor. 12
- 13. AVERAGE MEASUREMENTS Vertical - 3.5 cm Transverse - 2.5 cm Antero- posterior - 3.2 cm of base OPENING In intact skull the size of opening is reduced to 3-4mm as it is overlapped 13
- 14. RELATIONS ANTEROLATERALLY POSTERIORLY Infra-orbital plexus of nerves Infratemporal Infra –orbital veins Pterygopalatine fossa Origin of muscles of upper lip Posterior superior alveolar vessels and nerves Anterior superior alveolar vessels and nerves in Canalis Sinusus ( a bony canal ) 14
- 16. 16 •Facial •Infraorbital •Greater palatine ARTERIAL SUPPLY •Facial vein •Pterygoid plexus of veins VENOUS DRAINAGE •Submandibular lymph nodes LYMPHATICS •Infraorbital •Superior alveolar nerves (anterior,middle and posterior) NERVE SUPPLY
- 17. 17
- 18. FRONTAL AIR SINUS • Resides in frontal bone. • 2nd largest • Asymmetrical (triangular) • On average vertically- 3cm antero-posteriorly- 3cm transversally- 2.5 cm 18
- 19. NEUROVASCULAR SUPPLY ARTERY- Supra-orbital branch of opthalmic artery VEIN- Junction of supra-orbital and superior ophthalmic vein LYMPH NODE Submanibular lymph nodes NERVE - Supra-orbital branch of frontal nerve 19
- 20. ETHMOIDAL SINUS • Present in ethmoid bone • Classified as Anterior -1-11 air cells Middle- 1-5 air cells Posterior-1-7 air cells Relations Superiorly-Cranial Cavity Inferiorly- Maxillary air sinus Anteriorly- External nose Medially- Nasal cavity Laterally- Optic nerve and nasolacrimal duct 20
- 22. LYMPHATIC DRAINAGE Submandibular lymph nodes (anterior sinuses) Retropharyngeal lymph nodes(posterior sinuses) NERVE SUPPLY- 22
- 23. SPHENOIDAL SINUS • Present in sphenoid bone • Pair of sinus separated by septum • Approximately- 2*1.8*2cm 23
- 24. 24
- 25. 25
- 27. APPLIED ANATOMY • Maxillary sinus, frontal sinus • Developmental anomalies • Intrinsic diseases (originating from tissues within sinus) • Extrinsic diseases (arising from odontogenic tissues) 27
- 28. APPLIED ANATOMY OF MAXILLARY SINUS Sphenopalatine fossa approached. Oro-antral fistula Infraorbital crescent Antral puncture APPLIED ANATOMY OF FRONTAL SINUS Frontal sinusitis Vacuum frontal headache Howarth operation Sinus gallop 28
- 29. DEVELOPMENTAL ANOMALIES • Aplasia • Agenesis • Hypoplasia • Crouzon syndrome • Treacher collins syndrome • Binder syndrome 29
- 31. EXTRINSIC INFLAMMATORY PERIOSTITIS BENIGN ODONTOGENIC CYSTS ODONTOGENIC TUMORS FIBROUS DYSPLASIA 31
- 32. MUCOSITIS • Thickened sinus mucosa • Normal mucosa thickness -1mm thick not seen in radiograph • Inflamed (infectious or allergic )-10-15 times seen radiographically • Detectable as noncorticated Band Radiopaque 32
- 33. SINUSITIS • generalized inflammation of the paranasal sinus mucosa • Causes blockage of drainage through the osteomeatal complex • Pansinusitis • 3 types- ACUTE,SUBACUTE,CHRONIC 33
- 34. ACUTE SINUSITIS • AETIOLOGY A.EXCITING CAUSES • Nasal infections • Swimming and diving • Trauma • Dental infections B.PREDISPOSING CAUSES LOCAL GENERAL 1.Obstruction to sinus 1. Environment Ventilation and drainage 2. Poor general health 2.Stasis of secretions 3.Previous attack of sinusitis 34
- 35. PATHOLOGY OF SINUSITIS Acute inflammation of sinus Hyperaemia, exudation of fluid,outpouring of PMNs, increased activity of serous and mucous glands May be non –supperative or supparative Intially exudate is serous later becomes mucopurulent or purulent Destruction of mucosal lining Failure of ostium to drain Empyema 35
- 36. ACUTE MAXILLARY SINUSITIS ACUTE FRONTAL SINUSITIS ACUTE ETHMOID SINUSITIS ACUTE SPHENOID SINUSITIS CLINICAL FEATURES Headache Pain Oedema of cheek Nasal discharge Frontal Headache Tenderness Oedema of upper eyelid Nasal discharge Pain Oedema of lids Nasal discharge Swelling of middle turbinate Pain Oedema of lids Nasal discharge Swelling of middle turbinate 36
- 37. 37
- 38. CHRONIC SINUSITIS • Infections lasting for months or years 38
- 39. 39
- 41. COMPLICATIONS OF SINUSITIS 41 LOCAL •Mucocele •Osteomylitis ORBITAL •Inflammatory oedema of lids •Subperiosteal abscess •Orbital cellulitis •Orbital abscess •Superior orbital fissure syndrome •Orbital apex syndrome INTRACRANIAL •Meningitis •Extradural abscess •Subdural abscess •Brain abscess •Cavernous sinus thrombosis DESCENDING INFECTIONS •Otitis media •Pharyngitis •Tonsilitis •Laryngitis •tracheobronchit is FOCAL INFECTIONS •Polyarthritis •Tenosynovitis
- 42. POLYPS • The thickened mucuous membrane of a chronically inflamed sinus forms into irregular folds called polyps. 42
- 43. ANTROLITH • Radiographical features • Location- maxillary sinus • Periphery and shape-well defined ,smooth and irregular shape • Internal structure-radiopaque ,homogenous or heterogenous 43
- 46. PAPILLOMA 46 Present in ethmoial/maxilla ry sinus Appear as isolated polyp in sinus Homogenous radiopaque
- 47. OSTEOMA 47 Most common mesenchymal neoplasm Occur in frontal an ethmoidal sinuses Lobulated,sharp defined margin Homogenous and radiopaque
- 49. SQUAMOUS CELL CARCINOMA 49 Occur in maxillary sinuses Radiopaque Destroy sinus walls, Bone destruction, Widening of periodontal Ligament space Floor destroyed
- 50. EXTRINSIC 50
- 51. PERIOSTITIS Presence of one or more halo layer of new bone indicates periosteum inflammation. Radiographic features- Periosteal new bone formation- Thin or thick radiopaque line (onion skin) Centered directly above the inflammatory lesion 51
- 52. ODONTOGENIC CYSTS Radicular cyst Dentigerous cyst Mucus Retention Cyst 52
- 53. ODONTOGENIC TUMORS • Ameloblastoma • Myxoma Radiographic features oval or multilocular shape ,aggressive tumors lack border. Displace the floor of antrum Thinning of peripheral cortex Bony walls of sinus eroded. Tooth may be embedded 53
- 54. FIBROUS DYSPLASIA Radiographic features Posterior maxilla , not well defined Radiopaque- ground glass appearance , orange peel appearance 54
- 55. CONCLUSION 55
- 56. REFERENCES • Gray’s anatomy 39th edition • Robbins and cotran 8th edition • Oral radiology by White and pharaoh 6th edition • Bailey and love’s short practice of surgery 24 th edition • Textbook of oral an maxillofacial surgery by Kruger 6th edition • Oral and maxillofacial surgery by Daniel M. Laskin volume 1 • Orbans oral histology and embryology 56