Nose Paranasal Sinuses 2023-24 (3).pptx
Transcript
Nose & Paranasal Sinuses Dr Vehid Salih Dr Vehid Salih (with acknowledgement to Dr Yen Lin) https://doi.org/10.1093/rpsppr/rqac003 Learning Objectives Describe the nose anatomy & bones that comprise the boundaries of nasal cavity and septum. Describe the conchae in terms of structure and function. N...
Nose & Paranasal Sinuses Dr Vehid Salih Dr Vehid Salih (with acknowledgement to Dr Yen Lin) https://doi.org/10.1093/rpsppr/rqac003 Learning Objectives Describe the nose anatomy & bones that comprise the boundaries of nasal cavity and septum. Describe the conchae in terms of structure and function. Name, describe and identify positions of all the paranasal sinuses. Describe their relationship to the nasal cavity and their sites of drainage through its lateral wall. Recognise the different hypotheses on their function. Explain sinus innervation in relation to ‘referred’ pain. The Nose Located inferiorly & medially to the eyes Functions Breathing Warms and humidifies inspired air Olfaction Removes/traps pathogens & particulates Drains & clears sinuses/lacrimal ducts Anatomy Consists of pseudostratified epithelium + cilia Highly vascular and easily congested Nasal cavity = complex chamber located posterior to the vestibule and atrium of the nose Netter's Head and Neck Anatomy for Dentistry Nose Anatomy 3 pairs of bones form the root of the nose: Frontal (nasal process) Maxilla (frontal process) Nasal Because the root of the nose is made of bone, it is fixed 3 different major cartilages form the dorsum and apex of the nose: Septal Lateral nasal (upper nasal) Major alar (lower nasal) Netter's Head and Neck Anatomy for Dentistry Nose vascular supply & innervation The blood supply to the nose arises from 3 major arteries: Ophthalmic Maxillary Facial These vessels are derived from the external and internal carotid arteries. General sensory supply to the nose arises from branches of the ophthalmic (nasociliary) and maxillary (nasopalatine) divisions of the trigeminal nerve. Special sensory supply is provided by the olfactory Nasal Cavities Spaces within the anterior aspect of the cranium, located directly behind the external nose. The left and right cavities are separated in the midline by a central nasal septum (medial wall) and both chambers are also bounded by a roof, floor and lateral wall. Each cavity has three regions: vestibule, respiratory & olfactory The vestibule is located within the nares, it is lined by skin and houses hair follicles. The olfactory region is the most superior part of the cavity space, it is lined by olfactory epithelium and contains olfactory receptors. The large respiratory region lined by respiratory Nasal Cavities 3 large elevations, known as conchae, protrude from the lateral wall: All of the paranasal sinuses and the nasolacrimal duct drain into the lateral walls of the nasal cavity. The sphenopalatine foramen, located in the posterior portion of the lateral walls, connects the nasal cavity to the pterygopalatine fossa. Netter's Head and Neck Anatomy for Dentistry Nasal Cavity boundaries & relations Anatomy for your SDL) (use 3D complete Nasal Cavity Conchae Netter's Head and Neck Anatomy for Dentistry WHAT IS THEIR FUNCTION? The Paranasal Sinuses WHY DO WE STUDY THEM? Speech and voice resonance Clinical relevance Reducing weight of the skull Air warming and filtration Mucus production and storage Production of Nitric Oxide WHAT IS THEIR STRUCTURE? Evolutionary residuals Sinuses forms primarily through intrinsic growth and invasion of bone... or secondarily, occupying regions of developing face that experience little or no biomechanical load … HOW DO THEY Large cavities enclosed in skull bones and covered by mucus and cilia, connected to the nasal cavity through passages and apertures called ostia Paranasal Sinuses Features Paired Hollow cavities Air filled Bony walls Lined by respiratory epithelium (pseudostratified columnar epithelium) Openings that communicate with lateral wall of nose TeachMeAnatomy Connections with nasal cavity Frontal and anterior ethmoidal sinus openings F Middle ethmoidal opening Posterior ethmoidal Sphenoopening ethmoidal Recess for sphenoidal sinuses Sup Maxillary sinus opening Mid Inf Nasolacrimal duct opening Opening to pharyngotympanic tube S Summary of Paranasal sinus drainage Sinus Blood Supply Ophthalmic artery Blood supply to nasal cavity is profuse Maxillary sinuses are supplied by branches of the maxillary artery. Maxillary a. Frontal sinus is supplied by branches of the ophthalmic artery. Ethmoidal and Sphenoidal sinuses are supplied by branches of both maxillary & ophthalmic branches. Sinus Innervation Ophthalmic nerve Maxillary nerve Maxillary sinuses are supplied by branches of the maxillary nerve. Frontal sinus is supplied by branches of the ophthalmic nerve. Ethmoidal and Sphenoidal sinuses are supplied by branches of both maxillary & ophthalmic nerves. Why Can maxillary sinus infections cause toothache? The non-odontogenic referred “tooth pain” is from superior alveolar nerves passing through the maxillary sinus on their way to the upper teeth. Sinusitis As paranasal sinuses are continuous with nasal cavity, an upper respiratory tract infection can spread to sinuses; this can cause inflammation (particularly pain and swelling) of mucosa (= sinusitis). If more than one sinus is affected, AKA pansinusitis The alveolar process of upper molar teeth can be very close to the floor of maxillary sinus cavity. (In 10% of people they ‘communicate’) Infection can spread, theoretically, both ways. The alveolar nerves thus affected by swelling and direct pressure of Maxillary sinuses as consequence of sinus infection Case courtesy of Dr Bruno Di Muzio, Radiopaedia.org, rID: 12702 Ear Infection As auditory tube connects the middle ear and upper respiratory tract, it is a path by which infection can spread between these areas Infection of auditory tube causes swelling of mucous linings, and tube becomes blocked Results in diminished hearing SDL https://www.youtube.com/watch?v=iwwFPQk7SJU https://www.youtube.com/watch?v=RT0p-kxLJ2k TeachMeAnatomy KenHub Drake RL. Gray's anatomy for students. 4th ed. 2020. Liebgott B. The anatomical basis of dentistry. 3rd ed. Maryland Heights, MO: Mosby; 2011. Agur AMR, Dalley Ii AF. Grant's Atlas of Anatomy. 15th ed: LWW; 2023. SDL Questions to consider....... 1. 2. 3. 4. 5. 6. 7. What are the functions of the turbinates? Where does ostia for the maxillary sinus open? Why is the maxillary sinus most likely to be infected? Why do you get toothache from a sinus infection? How would you treat a persistent maxillary sinus infection? Which two bones make up most of the nasal septum? If the maxillary sinus is infected, which lymph nodes will be enlarged? Practice Questions 1. What is the epithelial lining of the respiratory region of the nasal cavity? A. B. C. D. Simple squamous Olfactory cells Pseudostratified ciliated Stratified columnar Practice Questions 2. Which structure marks the opening of the frontal, maxillary and anterior ethmoidal sinuses in the nasal cavity? A. B. C. D. Ethmoidal bulla Semilunar hiatus Superior concha Cribriform plate Practice Questions 3. The cribriform plate forms the roof of the nasal cavity. Which cranial bone does it belong to? A. B. C. D. Temporal Frontal Ethmoid Sphenoid Practice Questions 4. The bones of the nasal septum can be divided into two groups: paired and unpaired. Which of the following is an unpaired bone of the nasal septum? A. B. C. D. Nasal Maxillary Palatine Ethmoid Practice Questions 5. Which of the following is not an ethmoid sinus? A. B. C. D. Anterior Middle Medial Posterior Practice Questions 6. Which is the largest of the paranasal sinuses? A. B. C. D. Frontal Maxillary Ethmoid Sphenoid Practice Questions (Applied Anatomy) 7. A 22 year old man attends the emergency department with epistaxis following a rugby injury to the face. Which of the facial bones forms the posterior aspect of the nasal septum? A. B. C. D. Maxilla Nasal bone Vomer Palatine Practice Questions (Applied Anatomy) 8. What typically causes a nasal fracture? A. B. C. D. Blunt trauma Shearing forces Sharp force injury Low impact collisions Practice Questions (Applied Anatomy) 9. A patient is seen in the neurosurgery clinic with an MRI-confirmed pituitary adenoma. Surgical resection of the adenoma is planned. When considering the surgical approach, which paranasal sinus provides access to the pituitary gland? A. B. C. D. Frontal Sphenoid Ethmoid Maxillary
