Anatomy of the Nose and Paranasal Sinuses PDF
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National University Sudan
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This document provides an overview of the anatomy of the nose and paranasal sinuses, including the external and internal structures, types of sinuses, and their innervation. It explains the function and location of each part, offering a breakdown of the different elements.
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Anatomy of the Nose and Paranasal Sinuses 1. Anatomy of the Nose 1.1. External Nose Structure: The external nose consists of the nasal bones, cartilage (lateral, alar, and septal cartilages), and the overlying skin. Regions: Root: Area between the eyes where the nasal bones co...
Anatomy of the Nose and Paranasal Sinuses 1. Anatomy of the Nose 1.1. External Nose Structure: The external nose consists of the nasal bones, cartilage (lateral, alar, and septal cartilages), and the overlying skin. Regions: Root: Area between the eyes where the nasal bones connect. Bridge: The top portion of the nose. Apex: The tip of the nose. Nostrils: The external openings of the nasal cavity. 1.2. Internal Nose Nasal Cavity: Divided by the nasal septum into left and right cavities. Nasal Septum: Made up of the perpendicular plate of the ethmoid bone, the vomer bone, and the septal cartilage. Nasal Conchae (Turbinates): Superior, middle, and inferior conchae. These bony structures are covered by mucosa and help to increase the surface area for warming and humidifying inhaled air. Meatuses: Spaces below each concha (superior, middle, and inferior meatuses) that drain the paranasal sinuses and nasolacrimal duct. 1.3. Nasal Mucosa Epithelium: Pseudostratified ciliated columnar epithelium with goblet cells. Function: Warming, moistening, and filtering inhaled air. 2. Paranasal Sinuses 2.1. Overview Sinuses: Air-filled cavities within the frontal, maxillary, ethmoid, and sphenoid bones that open into the nasal cavity. 2.2. Types of Paranasal Sinuses Frontal Sinuses: Location: Above the eyes in the frontal bone. Drainage: Drains into the middle meatus. Maxillary Sinuses: Location: Located in the maxillary bones below the eyes. Drainage: Drains into the middle meatus. Ethmoid Sinuses: Location: Located between the eyes within the ethmoid bone. Drainage: Anterior Ethmoid Cells: Drain into the middle meatus. Posterior Ethmoid Cells: Drain into the superior meatus. Sphenoid Sinuses: Location: Located in the sphenoid bone behind the ethmoid sinuses. Drainage: Drains into the sphenoethmoidal recess, located above the superior concha. 3. Innervation of the Nose and Paranasal Sinuses 3.1. Sensory Innervation Olfactory Nerve (CN I): Provides the sense of smell. Olfactory fibers pass through the cribriform plate of the ethmoid bone. Trigeminal Nerve (CN V): V1 (Ophthalmic Division): Provides sensory innervation to the superior part of the nasal cavity via the nasociliary nerve. V2 (Maxillary Division): Provides sensory innervation to the inferior part of the nasal cavity and the paranasal sinuses via the nasal branches of the maxillary nerve. 3.2. Parasympathetic Innervation Facial Nerve (CN VII): The greater petrosal nerve (a branch of CN VII) carries parasympathetic fibers that synapse in the pterygopalatine ganglion. Postganglionic fibers innervate the nasal and palatine glands. 3.3. Sympathetic Innervation Sympathetic Fibers: Originating from the superior cervical ganglion and traveling with the internal carotid artery to the nasal cavity and sinuses. These fibers are involved in vasoconstriction. Summary Table Structure Location Drainage Innervation External Nose Nasal bones N/A N/A and cartilage Nasal Cavity Divided by the N/A V1 (Ophthalmic) and nasal septum V2 (Maxillary) nerves Frontal Sinuses Frontal bone Middle meatus V1 (Frontal nerve) Maxillary Maxillary bone Middle meatus V2 (Superior alveolar Sinuses nerves) Ethmoid Ethmoid bone Anterior into middle V1 (Ethmoidal nerves) Sinuses meatus; Posterior into superior meatus Sphenoid Sphenoid Sphenoethmoidal recess V1 (Sphenoidal nerve) Sinuses bone Olfactory Olfactory N/A Olfactory nerves Nerve (CN I) epithelium Trigeminal Nasal cavity N/A V1 (Ophthalmic) and Nerve (CN V) and sinuses V2 (Maxillary) nerves Facial Nerve Nasal glands N/A Parasympathetic fibers (CN VII) Sympathetic Nasal cavity N/A Sympathetic nerves Fibers and sinuses References 1. Standring, S. (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice. 42nd Edition. Elsevier. 2. Drake, R.L., Vogl, W., & Mitchell, A.W.M. (2014). Gray's Anatomy for Students. 3rd Edition. Elsevier. 3. Moore, K.L., Dalley, A.F., & Agur, A.M.R. (2018). Clinically Oriented Anatomy. 8th Edition. Wolters Kluwer.
