The Nasal Cavity & Paranasal Sinuses PDF

The Nasal Cavity & Paranasal Sinuses Biomedical Science Rhona Mann Intended Learning Outcomes By the end of the session students should be able to: To explore the structure of the nasal cavity and gain an understanding of its signi9cance. To iden;fy the posi;on and clinical signi9cance of...

The Nasal Cavity & Paranasal Sinuses Biomedical Science Rhona Mann Intended Learning Outcomes By the end of the session students should be able to: To explore the structure of the nasal cavity and gain an understanding of its signi9cance. To iden;fy the posi;on and clinical signi9cance of the various paranasal sinuses. To be able to demonstrate an understanding of the anatomy of these structures. To recognise the clinical signi9cance of these structures in rela;on to health and disease. The Nasal Cavity sensory The Nose is the primary sensory I organ responsible for smell. Primary an It also plays a part in respira;on and org speech produc;on. The NASAL CAVITY lies just behind the 2 nostrils and these form the interior of the nose. The nasal cavity makes up the respiratory system along with : 1. Paranasal Sinuses 2. Oral Cavity 3. Pharynx 4. Larynx. Posterior to nostries- VesCbule Area lying just posterior to the nostrils. Part of the nasal cavity most exposed to the environment! Because of this exposure area is lined with mul;ple layers of “skin”: stra;9ed squamous epithelium and this forms a protec;ve barrier. This area has s;R hairs :VIBRISSAE. These are embedded in the cell lining and covered with thick mucus. Respiratory Region This begins at the end of the ves;bular region and includes the en;re nasal cavity, apart from the olfactory region. This region has a cilliated pseudo- stra;9ed epithelium lining which contains goblet cells that secrete mucus forming the mucous membrane Olfactory Region This is located at the top part of the nasal cavity near the septum. It is lined with olfactory cells and olfactory mucosa. This mucosa houses millions of cilia containing olfactory receptor proteins that are responsible for the sense of smell. Walls and Boundaries of the Nasal Cavity Medial wall This refers to the septum dividing the nasal cavity into 2 equal sec;ons. Bony upper & lower parts of the septum are formed by the perpendicular plate of the ethmoid bone and the Vomer. The lower front part is formed by a quadrangular Hyaline car;laginous structure known as the SEPTUM CARTILAGE. The lower part of the smooth medial wall can be seen from the outside and is divided by the 2 nostrils  Superior border (roof) Anterior border (lateral wall) The 2 nasal bones, the lower part The lower parts of the nasal of the frontal bone, the cribiform bones, the car;lage aYached to plate (of the ethmoid bone) and them, the outer nose and the the sphenoid bone, make up the nostrils are there in the front part roof. of the nasal cavity Posterior border (back wall) The upper back and sides are bordered with a number of cranial bones including the Maxilla, Ethmoid bone, Pala;ne bone, Sphenoid bone, Lacrimal bone as well as the: Inferior concha Floor: Apart from keeping the nasal cavity separated from the oral cavity, the hard palate, formed by the pala;ne process of the maxilla and the pala;ne bones ( horizontal plates) also make up its smooth ]oor  The nasal and oral cavi;es are connected with each other through the Nasopharynx (at the back of the throat) The so^ palate and uvula (the ]eshy projec;on at the back of the throat) together move up to close oR this connec;on during ea;ng to prevent food from entering the nasal cavity. Time for a break! During this break and a^er the Lecture inves;gate What is meant by the term pseudo –stra,-ed has multiple in rela;on to Epithelium? Tissue thatand packed Layers of cells , Single Layered tightly together. H What is the func;on of the Olfactory bulb? Processes smell information. The Paranasal Sinuses These sinuses are air 9lled extensions of the nasal cavity. There are 4 of these sinuses, named according to the bone in which they are located: Maxillary, frontal, sphenoid & ethmoid Each sinus is lined with ciliated pseudostraCQed epithelium interspersed with mucus secreCng goblet cells. 1. Frontal 2. Ethmoid 3. Sphenoid 4. Maxillary Paranasal Sinuses The func;on of these sinuses has been much debated but the following are considered the most logical: Lightening the weight of the head. Suppor;ng the immune defence of the nasal cavity. Humidifying the inspired air. Increasing resonance of the voice. Paranasal sinuses conCnued…. The paranasal sinuses are formed during development by the nasal cavity eroding the surrounding bones. All the sinuses therefore drain back into the nasal cavity. Openings to the Paranasal sinuses can be found on the roof and lateral nasal walls.  Sinus openings of. Frontal Sinuses There are 2 frontal sinuses located within the frontal bone of the skull. They are the most superior of the sinuses. Roughly triangular in shape. Drainage via the Frontonasal duct. Opens out at the Hiatus Semilunaris within the Middle meatus of the nasal cavity. InnervaCon: Supraorbital nerve( branch of the Ophthalmic) Blood supply : Anterior Ethmoid artery( branch of Internal Caro;d) Sphenoid Sinuses These are situated within the Sphenoid bone. They open into the nasal cavity in an area superior/posterior to the Superior Concha known as the Spheno-ethmoidal recess. InnervaCon: Posterior Ethmoidal nerve ( branch of the Ophthalmic) and branches of the maxillary nerve. Blood supply: via the Pharyngeal branches of the maxillary arteries. Ethmoid Sinuses: There are 3 of these within the Ethmoid bone. Anterior: opens onto the Hiatus Semilunaris (Middle Meatus) Middle: Opens onto the lateral wall of the Middle Meatus. Posterior: Opens onto the lateral wall of the Superior Meatus. InnervaCon: Anterior & Posterior Ethmoid branches of the Nasociliary nerve and the maxillary nerve. Blood supply: Anterior Posterior Ethmoid arteries. Maxillary Sinuses Largest of the sinuses: located laterally and slightly inferior to the nasal cavity. Drain into the nasal cavity via the Hiatus Semilunaris underneath the Frontal Sinus opening. This is poten;ally a pathway for spread of infec;on: ]uid drainage from the Frontal Sinus can enter the maxillary sinus. InnervaCon: Branches of the Alveolar Nerve plus the Infraorbital Nerve. Blood Supply: Branches of Alveolar Arteries plus Infraorbital and Greater Pala;ne Arteries. Clinical Relevance of the Paranasal Sinuses As the sinuses are con;nuous with the nasal cavity, an upper RESPIRATORY TRACT INFECTION can spread to the sinuses causing in]amma;on and pain : SinusiCs. Consider posi;oning of pa;ent and use of aerosols if breathing is challenging The maxillary nerve supplies both the maxillary sinus and the maxillary teeth and in]amma;on of the maxillary sinus can present as TOOTHACHE.  Thank you for you aZenCon. If there is anything you wish to discuss or have any quesCons at all please feel free to contact me: [email protected]