#1 Nasal Cavity and Paranasal Sinuses [Student Version].pdf

Lecture Medicine Duration ~45 Mins MDSA20200 Nasal Cavity and Paranasal Sinuses Dr. Arman Rahman, MD, MPH, Ph.D. Introduction to Respiratory Biology MDSA20200 For Anatomy Lectures: For Anatomy Practicals: 8 lectures On a given day, all sc...

Lecture Medicine Duration ~45 Mins MDSA20200 Nasal Cavity and Paranasal Sinuses Dr. Arman Rahman, MD, MPH, Ph.D. Introduction to Respiratory Biology MDSA20200 For Anatomy Lectures: For Anatomy Practicals: 8 lectures On a given day, all scheduled students should attend for a 2pm start time Sequence from upper to lower Venue C232 airways & thoracic wall White coat + student card 3 practicals, 4 offerings of each. Must attend scheduled offering  Recommended Reading Moore’s Clinically Oriented Anatomy (9th or 8th Ed.) Chapter 4 – Thorax Chapter 8 – Head Chapter 9 - Neck 9th Ed. 8th Ed. Introduction to Respiratory Biology MDSA20200 How will I be assessed? End of Trimester Examination (100%) Anatomy SAQ’s (30%) Physiology SAQ’s (20%) Physiology Essays (50%) Topics for Today Nasal cavity: structure Nasopharynx and posterior rhinoscopy Nasal septum components Paranasal sinuses Turbinates, conchae and meatus Blood supply to nasal cavity Ethmoid bone Nerve supply of nasal cavity Nasal Cavity Nasal Cavity Extends from anterior nares (nostrils) to posterior nares Posterior to posterior nares is the nasopharynx Functional areas Cartilage of the Nose 2 x Lateral Cartilage 2 x Greater alar Cartilage 2 x Lesser alar Cartilage 1 x Septal Cartilage Nasal Cavity Posterior Nares Aka choanae Aka posterior nostrils Incision through posterior nasopharynx showing posterior view of nasal cavity Bony Structure of the Nasal Cavity Piriform Aperture 2 x Lateral walls 1 x Floor Lateral wall Lateral wall 1 x median wall (nasal septum) Nasal Septum Floor  Components of the Nasal Septum 1 1. Perpendicular plate of the ethmoid 3 bone 2 2. Vomer bone 3. Septal cartilage Lateral wall Lateral wall Nasal Septum Floor  Lateral Walls of the Nasal Cavity Concha Bony shelf of bone, usually 3 each side Superior + Middle are part of ethmoid bone Inferior its own bone Turbinate Is a conchae with its overlying nasal mucosa Meatus Lateral wall Lateral wall Is the space under a turbinate Superior, middle and inferior meatuses respectively Floor  Lateral Wall of the Nasal Cavity NB: Nasal septum has been removed to permit visualisation of the right lateral wall Function of Turbinates 1. Guide airflow 2. Heat air 3. Humidify air  Notable Contents of Meatuses Superior Meatus Ostia for posterior ethmoidal air cells Middle Meatus Frontonasal duct Ethmoidal bulla Hiatus semilunaris Ostia for anterior / middle ethmoidal air cells Ostium for maxillary sinus Inferior Meatus Opening for nasolacrimal duct  Nasolacrimal Duct Why does lacrimation elicit rhinorrhoea? Communication between medial canthus of eye and inferior meatus of ipsilateral nasal cavity Ethmoid Bone Contributes to nasal septum and lateral walls of nasal cavity Contains air cells Anterior, Middle, Posterior air cells Superior & Middle conchae Forms part of medial orbital surface  Ostia for ethmoidal air cells Anterior air cells Drain into the hiatus semilunarus Middle air cells Drain through ethmoidal bulla Posterior air cells Drain to the superior meatus  Ethmoid Bone – cont. Smooth orbital plate aka lamina papyracea Forms lateral surface of ethmoidal air cells Inferior Conchae Articulate laterally with their ipsilateral maxilla / palatine bone Considered part of the facial skeleton: Inferior nasal conchae Lacrimal bones Mandible Maxillae Nasal bones Palatine bones Vomer Zygomatic bones  Clinical - Ethmoid Bone Fracture of Cribriform Plate Occurs following head trauma CSF Rhinorrhoea may be a clinical sign Anosmia Medial Orbital Blowout Fracture Fracture of lamina papyracea following head trauma Dehiscence of Lamina Papyracea Congenital anomaly usually found incidentally on imaging Varying levels of orbital fat prolapse Patients usually asymptomatic  Clinical – Turbinectomy Partial or complete resection of turbinate Performed usually to alleviate obstructive syndromes e.g. turbinate hypertrophy May result in Empty Nose Syndrome Rare & late complication of turbinectomy Read more: Symptoms: Kuan, E.C., Suh, J.D. & Wang, M.B. Empty Paradoxical nasal obstruction Nose Syndrome. Curr Allergy Asthma Rep 15, Drying & crusting of nasal mucosa (atrophic rhinitis) 493 (2015). Persistent subjective dyspnoea https://doi.org/10.1007/s11882-014-0493-x Nasopharynx Nasopharynx Posterior nares to oropharynx Notable contents: Eustachian Tube (aka Pharyngotympanic Tube) Adenoids  Eustachian Tube Connects nasopharynx to middle ear Swallowing / yawning etc… opens eustachian tube and equalises pressure across tympanic membrane Perceived as distinct “popping” sound Air travel Middle ear infections (otitis media) can be caused by chronic paranasal sinusitis  Waldeyer’s Ring Pharyngeal tonsil Lymphoid tissue aggregations surrounding (adenoids) Tubal tonsil (v. near oro/nasopharynx torus tubularis) NB: adenoidectomy / tonsillectomy / adenotonsillectomy Palatine tonsil Lingual tonsil https://www.youtube.com/watch?v=n8uVZTm279k https://www.youtube.com/watch?v=tR8_p4GKX3o  Posterior Rhinoscopy Circle of lymphoid tissue aggregations Vomer Inferior Middle Turbinate Turbinate Eustachian Tube Opening Paranasal Sinuses  Paranasal Sinuses Air filled cavities in bones surrounding nasal cavity Lighten load of cranium Humidify inhaled air Immune functionality. Produce mucous + cilia moves it through ducts into the nasal cavity Function as crumple zone for facial trauma (protecting brain) Increases resonance of voice  Paranasal Sinuses Frontal sinus Ethmoidal Sinus (ethmoidal air cells) Maxillary Sinus Sphenoidal Sinus  Frontal Sinus Superior Meatus Superior Turbinate Middle Sphenoidal Turbinate Sinus Middle Meatus Inferior Turbinate Inferior Eustachian Meatus Tube Ethmoidal Bulla  Ostia for posterior ethmoidal air cells Ostium of Ostium for the frontonasal duct Sphenoidal Sinus Ostium for anterior ethmoidal air cells Semilunar Hiatus Eustachian Ostium of Tube Nasolacrimal Duct Ostia for middle Ostium for ethmoidal air cells Maxillary Sinus Neurovascular Supply to Nasal Cavity  Ophthalmic a. Ant. Ethmoidal a. Post Ethmoidal a. Sphenopalatine a. Kiesselbach’s plexus Is in Little’s area Septal branch of Superior labial artery Greater palatine a. Maxillary a. Facial a. Arterial Supply to Septum  What arteries make up Kiesselbach Plexus Function: Adjust the temperature of the inhaled air Clinical significance- Nosebleed/epistaxis Epistaxis Nasal Cavity Tamponade Sensory distribution of Trigeminal nerve (CNV) branches CN I Olfactory Ophthalmic Maxillary Sensory Innervation of the Nasal Cavity Sphenopalatine ganglion  Recommended Reading 9th Ed. 9th Edition → Chapter 8 – Head, Nose, p973 - 983 8th Edition → Chapter 8 – Head, Nose, p963 – 8th Ed. 973 Thank you