Physiology of Nose and Paranasal Sinuses
Ilknur Haberal, MD
Fellow
OHNS Department
University of Chicago
Chicago, IL
Jacquelynne P. Corey, MD
Associate Professor
OHNS Department
University of Chicago
Chicago, IL
Although the majority of people are more concerned about the external shape of their nose, its internal anatomy and physiologic activity are of greater curiosity for otolaryngologists. A review of the functions of the nose would consider the following classifications:
- Respiratory airway
- Temperature conditioning of the airway
- Humidity control of the inspiring air
- Filtration of the inspired air and the associated mechanisms of ciliary actions
- Olfaction
- The contribution of vocal resonance
- Nasal reflex activity
The nose has proved a difficult area to objectively assess because of the range of normal variation and its dynamic physiology. Nonetheless, a range of investigative tools is available of a quantitative and semiquantitative nature. These include analysis of symptoms by visual analog score or validated symptom-, disease-, or organ-specific questionnaires; assessment of mucociliary function (nasomucociliary clearance, ciliary beat frequency, electron microscopy); nasal airway evaluation (nasal peak flow, rhinomanometry, acoustic rhinometry); olfaction evaluation (UPSIT or other validated test); and assessment of immune function, particularly for nasal allergies. These tests are complementary to a careful clinical assessment, which may include diagnostic nasal endoscopy in the diagnosis and evaluation of therapeutic interventions.
- Review the various functions of the nose.
- Explain the mechanisms of different functions of the nose.
- Summarize the effect of vasomotor reflexes, emotions, environmental factors, and hormones on functions of the nose.
- Recognize the importance of the nose for the upper and lower respiratory airways.
- Describe how to evaluate nasal function objectively.
- Cite objective measurement methods to measure different nasal functions.
Embryology
- Infants are obligate nasal breathers. As the airway develops and the infants’ physiology matures, both nasal and oral breathing are possible.
- The nose is the major and most efficient means of respiration in adults.
- Geurlink NA. Nasal anatomy and physiology. In: Settipane GA, editor. Rhinitis. Rhode Island: New England and Regional Allergy Proceedings; 1984:52-6.
Anatomy
- Understand what the nose does and how the physiology of the nose is essential to understanding the pathophysiology of various disorders of the nose.
- Know how to evaluate various functions of the nose such as:
- Respiratory airway
- Conditioning of airway by temperature
- Humidity control of the inspired air
- Filtration of the inspired air and the associated mechanisms of ciliary action
- Olfaction
- The contribution of vocal resonance
- Initiation of the nasal reflex activity
- Sensation
- Immunology
- Geurlink NA. Nasal anatomy and physiology. In: Settipane GA, editor. Rhinitis. Rhode Island: New England and Regional Allergy Proceedings; 1984:52-6.
- Jones N. The nose and paranasal sinuses physiology and anatomy. Adv Drug Deliv Rev. 2001;51:5-19.
Pathogenesis
Understand the mechanisms of the following functions:
- Filtration
- Warming
- Humidification
- Protection of lower airways
- Differences in inspiratory and expiratory air currents
- Effect of changes in nasal anatomy; e.g., deviated nasal septum, polyps, or air currents
- Normal nasal cycle
- Paradoxical nasal obstruction
- Role of parasympathetic nerve supply
- Role of ciliated epithelium and mucociliary defense system
- Role of hypersensitivity to nasal inhalant allergens
- Role of macrophages, basophils, mast cells, leukocytes, and eosinophils in the removal of microorganisms and noxious materials
- Role of antibacterial/antiviral substances such as immunoglobulins, lactoferrin, lysozymes, and interferons
- Anatomy and mechanisms of the sense of smell
- Role of nasal resonance in speech
- Role of nasal reflexes including olfactory, trigeminal, and general vasomotor
- Brain DJ. Anatomy, physiology and ultrastructure of the nose. In: Mackay I, editor.Rhinitis mechanisms and management. London: Ebenezer Baylis & Son Limited; 1989:1-31.
- Cole P. Physiology of the nose and paranasal sinuses. In: Gershwin ME, Incoudo GA, editors. Diseases of the sinuses. New Jersey: Humana Press Inc.; 1996:33-51.
- Geurlink NA. Nasal anatomy and physiology. In: Settipane GA, editor. Rhinitis. Rhode Island: New England and Regional Allergy Proceedings; 1984:52-6.
- Moore-Gillion V. Olfactometry and the sense of smell. In: Mackay I, editor. Rhinitis mechanisms and management. London: Ebenezer Baylis & Son Limited; 1989:69-79.
Basic Science
Understand the mechanisms of the following functions:
- Filtration
- Warming
- Humidification
- Protection of lower airways
- Differences in inspiratory and expiratory air currents
- Effect of changes in nasal anatomy; e.g., deviated nasal septum, polyps, or air currents
- Normal nasal cycle
- Paradoxical nasal obstruction
- Role of parasympathetic nerve supply
- Role of ciliated epithelium and mucociliary defense system
- Role of hypersensitivity to nasal inhalant allergens
- Role of macrophages, basophils, mast cells, leukocytes, and eosinophils in the removal of microorganisms and noxious materials
- Role of antibacterial/antiviral substances such as immunoglobulins, lactoferrin, lysozymes, and interferons
- Anatomy and mechanisms of the sense of smell
- Role of nasal resonance in speech
- Role of nasal reflexes including olfactory, trigeminal, and general vasomotor
- Brain DJ. Anatomy, physiology and ultrastructure of the nose. In: Mackay I, editor.Rhinitis mechanisms and management. London: Ebenezer Baylis & Son Limited; 1989:11-31.
- Cole P. Physiology of the nose and paranasal sinuses. In: Gershwin ME, Incoudo GA, editors. Diseases of the sinuses. New Jersey: Humana Press Inc.; 1996:33-51.
- Geurlink NA. Nasal anatomy and physiology. In: Settipane GA, editor. Rhinitis. Rhode Island: New England and Regional Allergy Proceedings; 1984:52-6.
- Moore-Gillion V. Olfactometry and the sense of smell. In: Mackay I, editor. Rhinitis mechanisms and management. London: Ebenezer Baylis & Son Limited; 1989:69-79.
Genetics
Understand the genetic basis of some diseases related to various functions of the nose such as:
- Allergies
- Primary ciliary dyskinesia
- Cystic fibrosis
- Young syndrome
- Genetic variability in taste receptors
- Friedman KJ, Teichtahl H, De Kretser DM, et al. Screening Young syndrome patients for CFTR mutations. Am J Respir Crit Care Med. 1995;152 (4 Pt 1):1353-7.
- Jorissen M, Bertrand B, Eloy P. Ciliary dyskinesia in the nose and paranasal sinuses. Acta Otorhinolaryngol Belg. 1997;51:353-66.
- Smith JM. Epidemiology. In: Mygind N, Naclerio RM, editors. Allergic and nonallergic rhinitis clinical aspects. Copenhagen: TL Offset I/S; 1993:15-22.
- Cohen NA. The genetics of the bitter taste receptor T2R38 in upper airway innate immunity and implications for chronic rhinosinusitis. Laryngoscope. 2017 Jan;127(1):44-51.
Patient Evaluation
- Understand that the history and physical exam are the key features of any evaluation.
- Know which measurement methods are available and which methods are useful to evaluate the functions of the nose.
- Know that measurement tools for various nasal functions include analysis of symptoms by visual analog score, validated symptom questionnaire such as the SNOT-20, RQLQ, RSOM 3, Nasal Health Survey; assessment of mucociliary function (nasomucociliary clearance, ciliary beat frequency, electron microscopy); nasal airway patency (nasal peak flow, rhinomanometry, acoustic rhinometry, rhinostereometry); and olfaction (smell tests).
- Understand that tests are complementary to a careful clinical assessment in the diagnosis and evaluation of therapeutic interventions.
- Know that nasal congestion is an important symptom.
- Understand that nasal resistance to airflow may be increased or decreased by many factors that influence nasal patency, such as:
- -Increased resistance
- Infective rhinitis
- Allergic rhinitis
- Hyperventilation
- Vasomotor rhinitis
- Supine posture
- Ingestion of alcohol
- Cold air
- Aspirin
- Sympathetic antagonists
- -Decreased resistance
- Exercise
- Sympathomimetics
- Rebreathing
- Atopic rhinitis
- Erect posture
- Prostaglandin E2
- -Increased resistance
- Know the role and mechanism of nasomucociliary dysfunction in recurrent nasal infections.
- Understand the role of central conditions in the loss of the sense of smell such as Alzheimer’s disease, Parkinson’s disease, Huntington’s corrhea, and Korsakoff syndrome.
- Know the role of nasal conditions associated with olfactory dysfunction including acute coryza, allergic rhinitis, vasomotor rhinitis, sinusitis, nasal polyposis, septal deviation, nasal and paranasal sinus tumors, tumors of the nasopharynx, and granulomatous nasal conditions.
- Eccles R. Rhinomanometry and nasal challenge. In: Mackay I, editor. Rhinitis mechanisms and management. London: Ebenezer Baylis & Son Limited; 1989:53-67.
Measurement of Functional Status
- Understand how to measure the nasal airway objectively.
- Understand how to test the sense of smell.
- Know how to measure mucociliary dysfunction.
- Know the importance of these methods as related to clinical assessment.
- Understand that the subjective sensation of patient nasal dysfunction to airflow can be misleading in that the sensation of obstruction does not always correlate with objective measures of nasal patency.
- Understand the role of objective documentation of functional patency, smell, and ciliary function for surgical planning.
- Understand the role of diagnostic nasal endoscopy to provide a visual depiction of anatomy (limited in assessing function).
- Know the validated symptom, disease-specific, or organ-specific questionnaires:
- Roles of the two types of quality of life questionnaires: generic and specific. Generic instruments are designed to be applicable to patients in all health states. The most commonly used and the best validated are the Sickness Impact Profile (SIP), the Short Form-36 (SF-36), the Nottingham Health Profile (NHP), and the McMaster Health Index Questionnaire.
- Roles of validated organ-, disease-, or symptom-specific questionnaires such as the SNOT-20, RSOM-31, RQLQ, Nasal Health Survey, Chronic Sinusitis Survey, and Fairlay, etc.
- Know how to measure nasal patency:
- Acoustic rhinometry :
- The physics, types of information gained, techniques, and clinical utility
- Role of assessing both reversible and irreversible changes as well as percentage changes and comparison to normal values
- Anterior and posterior rhinomanometry
- The physics of rhinomanometry; i.e., assessment of the nasal airway/ simultaneous measurement of transnasal pressure and airflow
- The technique of measurement of resistance and the difference between active anterior and posterior types
- Role of rhinomanometry in demonstrating nasal dynamic changes in nasal airway during respiration
- Nasal peak flow meters
- Role of mini peak flow meters adapted for the measurement of nasal inspiratory peak flow to measure large changes in nasal resistance
- Understand the effect of effort in this measurement
- Acoustic rhinometry :
- Know nasal challenge or nasal provocation tests.
- Understand that these tests involve the administration of suspected allergens (specific challenges) or methacholine (nonspecific) directly into the nose in order to determine the nasal sensitivity of a test substance.
- Understand the role of these tests for the diagnosis of allergic rhinitis, for research purposes, and for evaluating sensitivity to industrial and occupational allergens.
- Understand the techniques of administration of the challenge; such as nasal drops, nasal lavages, nebulized droplets, powders, and allergen-soaked filter paper discs.
- Understand that the measurement of these responses to nasal challenge may be recorded and assessed by subjective complaints such as obstruction, hypersecretion, sneezing, and itching or by objective parameters such as acoustic rhinometry or rhinomanometry, or by measuring mediator levels or markers such as plasma proteins in nasal secretions.
- Realize that the most important aspect of the provocation test is the comparison of the objective parameters simultaneously with subjective complaints before and after the challenge with a particular allergen (or nonspecific agent).
- Know how to perform assessment of nasomucociliary function:
- Understand that there are three principal disorders of mucociliary clearance:
- Primary ciliary dyskinesia , a rare genetic deficiency of the ultrastructural apparatus required to propel the cilium, in which nasal nitric oxide is very low because of a deficiency of inducible nitric oxide synthase
- Acquired (secondary) ciliary dyskinesia principally resulting from microbial toxin-induced dysfunction of the energy pathways required for ciliary beating
- Abnormalities in the physicochemical properties of mucus, including reduced salt content/osmolality, which results in it being unsuitable in quality for cilia to move it (cystic fibrosis)
- Understand that nasal mucociliary clearance function can be evaluated by using rhinoscintigraphy, saccharin clearance time, or ciliary beat frequency.
- Recognize that the more common types of ciliary dysmotility syndromes are characterized by missing dynein arms, central microtubule pairs, inner sheath, radial spokes, or nexin links and that these disorders can be diagnosed by electron microscopy or scanning microscopy investigations of nasal mucosal biopsies.
- Understand that there are three principal disorders of mucociliary clearance:
- Know how to perform assessment of olfaction:
- Understand methods of measuring olfaction including the use of “smell bottles” with or without a “multiple choice” test; qualitative ”scratch and sniff” test such as the UPSIT (University of Pennsylvania Smell Identification Test) and olfactometry (which measures thresholds). Know the multiple other smell test options (Sniffin Sticks, BAST, etc.)
- Understand that threshold evaluation may not, in some patients, correlate closely with impairment of olfactory performance in everyday life. Patients may have problems with recognition of odors, and this problem is more marked with some odors than others. Clinicians should be aware of this and use alternative approaches.
- Understand that immunologic function, particularly allergic status, may be assessed by in vitro or in vivo testing methods.
- Barreto BA, Daher S, Naspitz CK, et al. Specific and nonspecific nasal provocation tests in children with perennial allergic rhinitis. Allergol Immunopathol (Madr). 2001;29:255-63.
- Cole P. Acoustic rhinometry and rhinomanometry. Rhinology. 2000;Suppl 16:29-34.
- Cole P. Pathophysiology and treatment of airway mucociliary clearance. A moving tale. Minerva Anestesiol. 2001;67:206-9.
- Corey JP, Kemker BJ, Nelson R, et al. Evaluation of the nasal cavity by acoustic rhinometry in normal and allergic subjects. Otol Head Neck Surg. 1997;117:22-8.
- Cowan MJ, Gladwin MT, Shelhamer JH. Disorders of ciliary motility. Am J Med Sci. 2001;321:3-10.
- Fisher EW, Lund VJ, Scadding KG. Acoustic rhinometry in rhinologic practice: discussion paper. J R Soc Med. 1994;87:411-3.
- Gliklich RE, Metson R. Techniques for outcomes research in chronic sinusitis. Laryngoscope. 1995;105:387-90.
- Hilberg O. Objective measurement of nasal airway dimensions using acoustic rhinometry: methodological and clinical aspects. Allergy. 2002;57(Suppl 70):5-39.
- Jang YJ, Myong NH, Park KH, et al. Mucociliary transport and histologic characteristics of the mucosa of deviated nasal septum. Arch Otolaryngol Head Neck Surg. 2001;128:421-4.
- Juniper EF. Measuring health related quality of life in rhinitis. J Allergy Clin Immunol. 1997;99:S742-9.
- Mamikoglu B, Houser SM, Corey JP. An interpretation method for objective assessment of nasal congestion with acoustic rhinometry. Laryngoscope. 2002;112:926-9.
- McLean JA. Nasal rhinometry and experimental nasal challenges. In: Settipane GA, editor. Rhinitis. Rhode Island: New England and Regional Allergy Proceedings; 1984:62-9.
- Moore-Gillion V. Olfactometry and the sense of smell. In: Mackay I, editor. Rhinitis mechanisms and management. London: Ebenezer Baylis & Son Limited; 1989:69-79.
- Pelikan Z. Late nasal response. In: Pelikan Z, editor. The late nasal response. Amsterdam: 1996:21-117.
- Rhee CS, Min YG, Lee CH, et al. Ciliary beat frequency in cultured human nasal epithelial cells. Ann Otol Rhinol Laryngol. 2001;110:1011-6.
- Rice DH, Gluckman JL. Physiology. In: Donald PJ, Gluckman JL, Rice DH, editors. The sinuses. New York: Raven Press; 1995:49-56.
- Schumacher MJ. Nasal conjection and airway obstruction: the validity of available objective and subjective measures. Curr Allergy Asthma Rep. 2002;2:293-306.
- Sun SS, Hsieh JF, Tsai SC, et al. Evaluation of nasal mucociliary clearance function in allergic rhinitis patients with technetium 99m-labeled macroaggregated albumin rhinoscintigraphy. Ann Otol Rhinol Laryngol. 2002;111:77-9.
Imaging
- Understand that, although magnetic resonance imaging (MRI) and computed tomography (CT) have been used to document physiologic changes in the nose (the nasal cycle) as well as anatomy for research purposes, these tests are not usually useful clinically for these purposes.
- Understand that appropriate imaging techniques may be used as ancillary methods in cases of sinusitis or to diagnose tumors or other masses.
- Mamikoglu B, Houser S, Akbar I, et al. Acoustic rhinometry and computed tomography scans for the diagnosis of nasal septal deviation, with clinical correlation. Otolaryngol Head Neck Surg. 2000;123:61-8.
Pathology
- Understand the role of cytology in allergies and microscopic evaluation for mucociliary disorders.
- Know that mucociliary dysfunction can be diagnosed by analysis of ciliary beat frequency or scanning microscopy investigations of nasal mucosal biopsies.
- Understand that nasal smears can be used for the diagnosis of allergic nasal diseases, nonallergic nasal diseases, and nonallergic rhinitis with eosinophilia syndrome.
- Cole P. Pathophysiology and treatment of airway mucociliary clearance. A moving tale. Minerva Anestesiol. 2001;67:206-9.
- Smith JM. Epidemiology. In: Mygind N, Naclerio RM, editors. Allergic and nonallergic rhinitis clinical aspects. Copenhagen: TL Offset I/S; 1993:15-22.
Medical Therapies
Know that a clear understanding of nasal physiology and use of appropriate ancillary tests with a good history and physical exam (including an endoscopic nasal exam) may aid in the choice of therapies.
- For example, acoustic rhinometry can indicate the component of nasal obstruction that is fixed or reversible and its level to aid in surgical planning.
- Corey JP, Kemker BJ, Nelson R, et al. Evaluation of the nasal cavity by acoustic rhinometry in normal and allergic subjects. Otol Head Neck Surg. 1997;117:22-8.
- Mamikoglu B, Houser SM, Corey JP. An interpretation method for objective assessment of nasal congestion with acoustic rhinometry. Laryngoscope. 2002;112:926-9.
Case Studies
- A 34-year-old female with chronic nasal obstruction, seasonal and perennial allergic rhinitis, and smell dysfunction presented to the clinic. She had tried many allergic medications in the past and was denied sufficient relief. In vitro allergy tests were positive for dust and ragweed in the past. She was recently taking a nasal steroid, an antihistamine, and an antileukotriene medication. She has been on specific immunotherapy for one year. Ear, nose, and throat exam including nasal endoscopy showed bilateral inferior turbinate hypertrophy. CT scan of sinuses was reported as normal. Acoustic rhinometry showed reversible nasal congestion that was consistent with her allergic state. A smell test (UPSIT) score was within normal limits. A SNOT-20 documented severe symptoms. Bilateral nasal turbinate somnoplasty was performed. Six months after the operation, a SNOT-20 questionnaire showed improvement of symptoms from severe (preprocedure) to mild (postprocedure).
- A five-year-old boy with recurrent sinus infection, nasal polyposis, persistent greenish and very thick nasal discharge, frequent pneumonia episodes, and bilateral serous otitis media presented to the clinic. He was taking antibiotics constantly to suppress the pneumonia episodes. On examination, a greenish thick mucus was aspirated from the nasal cavities. Nasal endoscopy showed bilateral nasal polyposis. CT scan showed pansinusitis and nasal polyposis.
- Cystic fibrosis with mucociliary dysfunction was the differential diagnosis for this child.
- A sweat test showed high chloride levels, which was consistent with cystic fibrosis.
- A nasal biopsy was taken for this patient. Electron microscopy of the nasal biopsy showed dynein arm defect of nasal cilia, which supported primary ciliary dyskinesia.
- Cystic fibrosis gene testing showed positive findings consistent with cystic fibrosis. Cystic fibrosis carrier testing was offered to the parents and genetic counseling was given.
Review
- What is the most important function of the nose?
- What are the other functions of the nose?
- How do hormones affect the nose?
- What is the nasal cycle?
- What is paradoxical nasal obstruction?
- How does the nose humidify and warm the inspired air?
- What kinds of factors affect the mucociliary function of the nose?
- Where are the olfactory neurons located?
- What is the nasopulmonary reflex?
- What is the mechanism of vasomotor rhinitis?
- Discuss the methods by which to evaluate the sensation of nasal obstruction.
- Which factors increase nasal resistance?
- When do you use nasal challenge testing?
- Describe the signs and symptoms of the nasomucociliary dysfunction.
- How do you test nasomucociliary function?
- How can you test the sense of smell?
- What is the most common immune function assessment needed for evaluation of the nose?
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- Sinus and Nasal Anatomy