The Nasal Cavity and Paranasal Sinuses and Pharynx PDF

The Nasal caity , paranasal sinuses and pharynx Paria SHOJAOLSADATI, assistant professor in human anatomy School of Medicine Department of Anatomy Attention! Terminology “Respiration” is used several different ways: “Cellular respiration” is the aerobic breakdown of glucose in the mitochondria to ma...

The Nasal caity , paranasal sinuses and pharynx Paria SHOJAOLSADATI, assistant professor in human anatomy School of Medicine Department of Anatomy Attention! Terminology “Respiration” is used several different ways: “Cellular respiration” is the aerobic breakdown of glucose in the mitochondria to make ATP. Respiratory systems are the organs in animals that exchange gases with the environment. “Respiration” is an everyday term that is often used to mean “breathing.” Respiratory system Functions classification of respiratory system Upper respiratory tract Conducting passages (Airways) Lower respiratory tract Respiratory System Main organ of gaz Exchange (Lunges) Anatomic divisions of respiratory tract Anatomic divisions of respiratory tract Upper respiratory tract (outside thorax)     Nose Nasal Cavity Paranasal sinuses Pharynx Anatomic divisions of respiratory tract Lower respirator tract (within thorax)     Larynx Trachea Bronchial Tree Lung Functions of the nose and the nasal cavities Olfaction (sense of smell) Respiration Absorption Filtration of the dust in the inspired air (vibrissae) Humidification and warming of the inspired air (cooling the internal carotid artery for brain) Reception of the secretions from the paranasal sinuses and nasolacrimal ducts Nose Nose is divisible into two parts External nose Nasal cavity External Nose Dorsum Root Apex Nares (nostrils, anterior nasal apertures) Alae of the nose External Nose External nose has bony and cartilaginous parts: Bones contributing to the structure of the external nose Nasal bones Frontal process of maxilla Nasal part of frontal bone External Nose Cartilages contributing to the structure of the external nose: Lateral nasal cartilages (paired) Greater alar cartilages (paired) Lateral crus Medial crus Lesser alar cartilages Acessory (sesamoid) alar cartilages Septal cartilage (single) External Nose External nose has bony and cartilaginous parts: Nasal cavity The nasal cavity extends from the nostrils in front to the posterior nasal apertures or choanae behind. This is where the nose opens into the nasopharynx. The nasal vestibule is the area of the nasal cavity lying just inside the nostril. Nasal cavity The nasal cavities extend from the anterior apertures (nares) to the posterior apertures (choanae). The nasal cavities are separated: from each other by a midline nasal septum. from the oral cavity below by the hard palate. from the cranial cavity above by parts of the frontal, ethmoid, and sphenoid bones. Each nasal cavity has: Floor. Roof. Medial wall. ateral wall. Nasal cavities (anterolateral view). Relationship to other cavities. Bony entrance of nasal cavity  piriform aperture; maxilla and nasal bone ANA: Skull - 59 Roof of nasal cavity Roof: Formed by:  Body of sphenoid.  Cribriform plate of ethmoid bone.  Frontal bone.  Nasal bone. Floor of nasal cavity Floor: Formed by the hard palate (palatine process of the maxilla, and the horizontal plate of the palatine bone ) 10/27/2014 Medial wall of nasal cavity Medial Wall (Nasal Septum): Formed by: Superiorly by the vertical (perpendicular) plate of ethmoid bone. Posteriorly by the vomer bone. Anteriorly by the septal cartilage. Small contributions by frontal, palatine, sphenoid and maxillary bones. Nasal septum  nasal septum: perpendicular plate of ethmoid + vomer Nasal cavity Nasal septum separates the right and left nasal cavities. Nasal septum is composed of three structures: Perpendicular plate of the ethmoid bone Vomer Septal cartilage Nasal septum Crista Galli Perpendicular Plate of the Ethmoid Bone Cribriform Plate Cartilaginous Septum Hard Palate Vomer Palatine Bone Lateral wall of nasal cavity The lateral wall of each nasal cavity is complex and is formed by bone, cartilage, and soft tissues. Bony support for the lateral wall is provided by: the the the the the ethmoidal labyrinth and uncinate process. perpendicular plate of the palatine bone. medial plate of the pterygoid process of the sphenoid bone. medial surfaces of the lacrimal bones and maxillae. inferior concha. Lateral wallLateral of nasalwall cavityof nasal cavity  Inferior nasal chonae Ethmoid bone Openings on Lateral wall of nasal cavity  Sphenopalatine foramen opens from nasal cavity to pterygopalatine fossa.  further posteriorly, the medial surface of the medial pterygoid plate completes the lateral wall Medial pterygoid plate, palatine bone ANA: Skull - 65 Lateral wall of nasal cavity The lateral wall is characterized by three curved shelves of bone (conchae), which are one above the other and project medially and inferiorly across the nasal cavity. The conchae divide each nasal cavity into four air channels: an inferior nasal meatus between the inferior concha and the nasal floor. a middle nasal meatus between the inferior and middle concha. a superior nasal meatus between the middle and superior concha. a sphenoethmoidal recess between the superior concha and the nasal roof. 10/27/2014 The medial wall has a smooth surface, whereas the lateral wall is uneven due to the existance of the nasal conchae The spaces between the nasal conchae and the lateral wall of the nasal cavity are called the meatus. Superior nasal meatus Middle nasal meatus Inferior nasal meatus Nasal airflow These Conchae increase the surface area of contact between the lateral wal and respired air. 30 Choana Posteriorly, nasal cavities communicate with the nasopharynx through two openings called choana. is bordered by: Vomer (medial) Medial lamina of the pterygoid process of the sphenoid bone (lateral) Horizontal plate of the palatine bone (inferior) Body of sphenoid bone (superior) Choana Functional divisions of the nose Each nasal cavity is divided into Olfactory area (upper 1/3) Respiratory area (lover 2/3) Functional divisions of the nose Functional divisions of the nose Olfactory region (upper 1/3) Respiratory region (lower 2/3) Vestibulum 35 Arteries of the nose The arterial supply to the nasal cavity is from branches of the maxillary artery, one of the terminal branches of the external carotid artery. The most important branch is the sphenopalatine artery. The sphenopalatine artery anastomoses with the septal branch of the superior labial branch of the facial artery in the region of the vestibule. The submucous venous plexus is drained by veins that accompany the arteries. Arteries of the nose Sphenopalatine artery (from maxillary) Anterior ethmoid arteries (from ophthalmic) Posterior ethmoid arteries (from ophthalmic) Greater palatine artery (from descending palatineMaxillary artery branch) Superior labial artery (from facial) Arteries of the nose Veins of the nose There is a rich network of veins deep to the mucosa of the nose. This venous network is important in warming the air before it enters the trachea and the lungs. Veins drain into Sphenopalatine vein Facial vein Ophthalmic vein Nerves of Nasal Cavity The olfactory nerves from the olfactory mucous membrane ascend through the cribriform plate of the ethmoid bone to the olfactory bulbs. The nerves of ordinary sensation are branches of the ophthalmic division and the maxillary division of the trigeminal nerve. İncisive canal Anterior palatine foramen Clinical note Nasopalatine nerve block This type of anesthesia is solely used for dental procedures and done when all other blocks could not achive adequate anesthesia of the desired individial tooth. Clinical note Nasal fractures Due to its prominence, the nasal fractures are common Usually nasal deformity is visible and epistaxis (bleeding through the nose) occurs Clinical note Deviation of the nasal septum May be due to birth injury or trauma in any age Common cause of sinusitis due to insufficient ventilation and drainage of the sinuses Can be surgically repaired Paranasal sinuses Air filled spaces lying within the bones around the nasal cavity. The inner surface of the sinuses is covered by the mucosa. They are named according to the bones they are located in. Frontal sinuses Ethmoid sinuses Sphenoid sinuses Maxillary sinuses Paranasal sinuses Paranasal sinuses Paranasal sinuses communicate with nasal cavities and nasopharynx frontal sinus, ethomidal air cells, maxillary & sphenoidal sinus ANA: Skull - 69 Frontal sinus Frontal sinus Lie within the inner an outer plates of the frontal bone, posterior to the supercilliary arches and the root of the nose. The opening of the sinus is called the frontonasal duct. Drains into the middle nasal meatus Ethmoid sinuses Ethmoid sinuses Several ethmoid air cells (3-15) collectively are called the ethmoid sinuses. Middle Ethmoid air cells open into the middle meatus Sphenoid sinus Situated within the body of the sphenoid bone Sinuses of each side is seperated by a bony septum Drains into the sphenoethmoidal recess Maxillary sinus Lies within the body of the maxilla Maxillary opening drains into the middle nasal meatus The maxillary sinuses are innervated by infra-orbital and alveolar branches of the maxillary nerve [V2] receive their blood through branches from the infra-orbital and superior alveolar branches of the maxillary arteries Relationships of the Maxillary sinus 58 Maxillary Molars and the Maxillary Sinus The roots of the maxillary molars bulge into the floor of the maxillary sinus but normally do not perforate the mucus membrane of the sinus. Extreme care must be given when extracting the maxillary molars because a fractured root may be driven into the maxillary sinus, forming a communication between the oral cavity and the maxillary sinus and thus increasing the chance of sinus infection. Clinical note Maxillary sinusitis Maxillary sinuses are the most commonly infected sinuses Due to the edema, its opening may be obstracted PHARYNX Pharynx Common to both the respiratory and digestive systems. Commonly called the throat. Funnel-shaped slightly wider superiorly and narrower inferiorly. Originates posterior to the nasal and oral cavities A common pathway for both air and food. 25-76 Pharynx Pharynx is a tubular organ about 13-15 cm long Pharynx is composed of mucosa, muscles and connective tissue Extends from the base of the cranium to the level of C6 vertebra Inferiorly continues with the esophagus Pharynx Walls: lined by a mucosa contain skeletal muscles primarily used for swallowing. Flexible lateral walls distensible to force swallowed food into the esophagus. Partitioned into three adjoining regions: nasopharynx oropharynx laryngopharynx 25-78 Pharynx The lumen of pahrynx is divided into three parts in accordance with its anterior relations Nasopharynx Oropharynx Laryngopharynx Pharynx Important Landmarks Nasal Cavity 1 Soft Palate Hard palate Oral Cavity 2 Epiglottis 3 Cricoid Cartilage Nasopharynx 1 Oropharynx 2 Larygopharynx Larynx 3