1. Anatomy and Physiology of Nose and Paranasal Sinuses Dr. Krishna Koirala 2019-11-05

2. External Nasal Framework Nasal Bone Frontal Process of Maxilla Upper Lateral Nasal Cartilage Lower Lateral Nasal (Alar) Cartilage Septal Cartilage Lesser Alar (Sesamoid) Cartilages

3. Internal Nose Openings : Anterior and posterior nares Vestibule of nose : lined by skin,contains hair follicles Nasal cavity proper : Lateral Wall, Medial Wall (Septum), Roof, Floor

4. 1. Septal cartilage 2. Ethmoid plate 3. Vomer 4. Palatine crest 5. Maxillary crest 6. Vomeronasal cartilage 7. Medial alar crus 8. Upper lateral cartilage 9. Nasal bone crest 10. Frontal spine 11. Sphenoid rostrum 12. Membranous septum Nasal Septum

5. Lateral Nasal Wall Vestibule of nose : lined by skin,contains hair follicles 3 - 4 bony conchae are covered with mucosa to form the turbinates Space below and lateral to turbinate is called meatus Middle meatus contains a round bulla ethmoidalis separated from uncinate process by hiatus semilunaris that leads to a funnel shaped ethmoidal infundibulum

9. Meatal Drainage 1. Inferior meatus: Nasolacrimal duct 2. Middle meatus: Frontal, anterior ethmoid, maxillary 3. Superior meatus : Posterior ethmoid 4. Spheno - ethmoidal recess: Sphenoid

11. Ostio -meatal Complex Complex micro-architectural pathway in ethmoid labyrinth that drains anterior group of paranasal sinuses Consists of –Frontal recess, ethmoid infundibulum, hiatus semilunaris, uncinate process, bulla ethmoidalis, middle meatus O.M.C. pathology leads to infection of all anterior paranasal sinuses (Naumann)

12. O.M.C. Variants Concha bullosa (pneumatized middle turbinate) Paradoxically curved middle turbinate Medially turned ( bent) uncinate process Large bulla ethmoidalis Haller’s cell ( orbital floor) Agger nasi cell (anterior to middle turbinate) Mucosal pathology

13. Concha Bullosa

14. Paradoxically curved M.T.

15. Large bulla ethmoidalis

16. Blood Supply 1.Sphenopalatine artery (main artery) 2.Greater palatine artery 3.Superior labial artery 4.Anterior Ethmoidal artery 5.Posterior Ethmoidal artery 1, 2, 3 & 4 form Kiesselbach’s plexus over Little’s area on anterior septum

17. Blood supply of Nasal septum

18. Blood supply of lateral nasal wall

20. Venous Drainage Ethmoidal veins  ophthalmic veins  cavernous sinus Sphenopalatine vein  pterygoid plexus  maxillary vein Woodruff’s venous plexus : present on lateral wall near the posterior end of middle turbinate Retro - columellar vein: behind the columella

21. Autonomic Nerve Supply Deep petrosal nerve (sympathetic) + greater superficial petrosal nerve (parasympathetic)  Vidian nerve  pterygo- palatine ganglion  nasal glands Sympathetic stimulation  vasoconstriction +  ed nasal secretions Para-sympathetic stimulation  vasodilatation +  ed nasal secretions

22. Lining Epithelium –Skin: on the nasal vestibule –Olfactory epithelium: upper 1/3 rd of nasal cavity above the superior turbinate –Respiratory epithelium (pseudo-stratified ciliated columnar) : rest of nasal cavity + paranasal sinus Lymphatic Drainage: –External nose & anterior nasal cavity : Submandibular LN –Remaining nasal cavity : Upper deep cervical lymph nodes –Nasal roof (dangerous area of nose) : Subarachnoid space along the olfactory nerve –P.N.S. : Retropharyngeal & J.D. node

23. Paranasal Sinuses Anterior group –Frontal –Anterior ethmoidal –Maxillary Posterior group –Posterior ethmoidal –Sphenoid

24. Development of P.N.S. Appear first First X-ray appearance Reach adult size by MaxillaryAt birth4 mth15 yr EthmoidalAt birth1yr12 yr Sphenoid2 yr4 yr18 yr Frontal4 yr6 yr15 yr

25. Physiology of Nose & PNS, Olfaction

26. Functions of Nose Respiration –Heat exchange –Humidification –Filtration –Nasal resistance –Nasal fluids & cilliary function –Nasal neurovascular reflexes –Voice modification Olfaction Functions of PNS

27. Respiration Inspiration –Air current passes along mid- portion of nasal cavity in lamellar flow Expiration –Resistance of nasal valve & turbinates leads to formation of eddy current in expired air –Results in awareness of breathing and ventilation of paranasal sinus

28. Air conditioning Filtration : Particles > 3 μm in inspired air are trapped by nasal vibrissae Temperature control –Heat exchange between blood in cavernous venous sinusoids of turbinates and inspired air (radiation) Humidification –secretions of nasal & PNS mucosa; for better ciliary function

29. Protection of lower airway Muco-ciliary blanket : traps pathogens in inspired air > 0.5 μm & transports them to nasopharynx for swallowing Sneezing : protects against irritants Lysozyme : kills bacteria & viruses Immunoglobulins A & E : protection against bacteria Interferon : for protection against virus

30. Muco-ciliary blanket Goblet cells in nasal mucosa secrete a mucous blanket that moves backwards like a conveyer belt into the nasopharynx Consists of superficial mucous or gel layer and deep serous or sol layer

31. Factors decreasing mucociliary function Dry atmosphere (absence of humidity) Smoking, air pollutants, nasal irritants Infection Extremes of temperature Hypoxia Drugs: anesthetics, sedatives, beta blockers, topical nasal decongestants

32. Ventilation of PNS Inspiration –Negative pressure created in nasal cavity sucks out air from paranasal sinuses via their ostium Expiration –Eddies within nasal cavity create positive pressure that ventilates paranasal sinuses via their ostium

33. Drainage of the sinuses Anterior sinuses drain in lateral pharyngeal gutter Posterior sinuses drain over posterior pharyngeal wall

34. Nasal resistance Nasal resistance to expired air (by nasal valve) keeps positive pressure in respiratory tract & prevents alveolar collapse

35. Vocal Resonance Nasal cavity & paranasal sinuses provide vocal resonance for nasal consonants M, N, nG De-nasal voice( Hyponasal Voice) –Seen in nasal obstruction – Nasal consonants M, N & nG pronounced as B, D & G respectively

36. Nasal Reflexes Smell reflex : Increases secretions of saliva & gastric juice Naso-pulmonary reflex : Chronic, severe nasal obstruction leads to increased pulmonary resistance and pulmonary hypertension Sneeze reflex : Protection against F.B., irritants

37. Nasal Cycle Reflex, periodic alternation in nasal airflow resistance between two nasal cavities Regulated by autonomic nervous system Due to congestion & decongestion of venous sinusoids of inferior turbinates & anterior nasal septum Each cycle lasts for 4 -12 hours

38. Factors modifying nasal cycle Temperature & humidity of surrounding air Head position Body temperature Physical activity Emotional & psychological status Hypothyroidism & hyperthyroidism Nasal decongestants & anti- hypertensives

39. Olfaction

40. Olfactory area of nose Located on the roof of the nasal cavity –Cribriform plate –Superior part of the nasal septum –Superior turbinate –Upper part of middle turbinate

41. Olfactory neural pathway Olfactory receptors on nasal mucosa  Olfactory nerve bundles (20)  synapse with Mitral & Tufted cells in Olfactory bulb  Axons unite to form Olfactory tract  flattens distally to form Olfactory trigone  trifurcates into Olfactory striae  synapse with 1 0 & 2 0 Olfactory cortex + hypothalamus + hippocampus + amygdala

44. Olfaction is the only sensation to reach cerebral cortex directly without first relaying at thalamus Olfactory pathway incorporates limbic system & is concerned with emotional behaviour, mood & recent memory

45. Causes of Olfactory dysfunction 1. Upper respiratory viral infection (30 %) 2. Idiopathic (25 %) 3. Head trauma (20 %) 4. Obstructive sinonasal disease (15 %) : Rhino –sinusitis, nasal polyp, neoplasm 5. Neurologic & Psychiatric diseases 6. Intra-cranial neoplasm 7. Toxic chemicals & surgical trauma

46. Classification Conductive loss: obstruction of nasal passages – Chronic nasal inflammation, polyposis Sensorineural loss: damage to neuroepithelium – Viral infection, airborne toxin Central olfactory neural loss: C.N.S. damage – Tumors, neurodegenerative disorders

47. Types of Olfactory dysfunction 1. Anosmia: absence of olfactory sensation 2. Hyposmia: decreased olfactory sensation 3. Parosmia / cachosmia: perception of a pleasant odour as unpleasant odour 4. Phantosmia: perception of odour in absence of olfactory stimulus 5. Hyperosmia: increased olfactory sensation 6. Olfactory agnosia: unable to identify odour

48. Olfactory function tests 1.Supra-threshold test: only identifies odour –Smell bottles –Smell Identification Test (S.I.T.) 2. Threshold Olfactometry: measures weakest perceptible odour with help of serial dilution –Manual –Dynamic (automated)

49. Manual Threshold Olfactometry

50. Dynamic Threshold Olfactometry

51. University of Pennsylvania Smell Identification Test (UPSIT) Most commonly used test of smell worldwide 4 booklets of 10 microencapsulated odors stimuli Scratch and sniff format Four responses accompanying each odor Forced choice design Scores are compared to normal (sex- and age-related)

52. Smell Identification Test sample

53. Results 36 – 40: Normal 16-35: Partial anosmia 6-15 : Total anosmia 0-5: Malingering