Nose Anatomy Lecture Slides PDF

ANA 311: The Nose, Nasal cavities Paranasal sinuses Dr. Okonta, E M Dept. Of Anatomy Bingham University, karu. Information This is a lecture slide for a lecture that was delivered to 300level BSc Anatomy and Physiology, MBBS students The presenter, in this case the lec...

ANA 311: The Nose, Nasal cavities Paranasal sinuses Dr. Okonta, E M Dept. Of Anatomy Bingham University, karu. Information This is a lecture slide for a lecture that was delivered to 300level BSc Anatomy and Physiology, MBBS students The presenter, in this case the lecturer, bears no responsibility for missing slides, text and or refrences that results from students sharing the slide and culminates into plagiarism All works have been adequately referenced OBJECTIVES At the end of the Lectures, if students were attentive enough it is expected they should be able to describes, with relevant details the anatomy of the following 1. The nose 2. Nasal Cavity 3. The paranasal Cavity CONTENTS Introduction External nose Nasal cavities Vasculature and innervation of nasal cavities Paranasal sinuses Development of the nasal cavity Applied/Clinical anatomy Conclusion References INTRODUCTION The nose is the first visible part of the respiratory system located superior to the hard palate The nose houses the peripheral organ of smell. The nose consists of the external nose, left and right nasal cavity The nose is saddled with olfaction (smelling), respiration (breathing), filtration and humidification of inspired air, and reception and elimination of secretions from the paranasal sinuses and nasolacrimal ducts. EXTERNAL NOSE Lateral view of the external nose courtesy COA EXTERNAL NOSE The most visible part of the nose, pyramidally shaped and projects forward from the face. Its upper end/root is continuous with the forehead while the lower end/base are the nares (nostrils). At the midline, anteriorly, the sides of the noses forms the dorsum. The upper part of the dorsum is the bridge , the lower end of the dorsum is the tip of the nose. The lower flared part of the side of the nose is the ala. EXTERNAL NOSE The skin on it is arranged specifically with certain specializations The skin covering the cartilages of the nose is thicker with many sebaceous glands. An extension of the skin into the vestibule of the nose has stiff hairs (vibrissae) The junction of the skin and mucous membrane is beyond the hair-bearing area EXTERNAL NOSE External nose and nasal septum courtesy of BRS Anatomy EXTERNAL NOSE The blood supply is by the dorsal nasal artery (a terminal branch of the ophthalmic) , from the root, and lower down by the external nasal artery (from the anterior ethmoidal) and by lateral nasal and septal branches of the facial artery and its superior labial branch. The skin is supplied by the external nasal nerve (the terminal part of the anterior ethmoidal, which courses the inner surface of the nasal bone); The infratrochlear branch of the nasociliary nerve and nasal branches of the infraorbital nerve also contribute to the supply of nasal skin EXTERNAL NOSE The skeletal framework is made up of nasal bones and hyaline cartilages The bony part of the nose consists of the nasal bones, frontal processes of the maxillae, the nasal part of the frontal bone and its nasal spine, and bony parts of the nasal septum The cartilaginous parts includes: two lateral cartilages, two alar cartilages, and one septal cartilage EXTERNAL NOSE The paired nasal bones articulate posteriorly with the maxillae and superiorly with the frontal bones. There is fusion of the periosteum and perichondrium inferiorly. The nasal bones slighty covers the superior margins of the (upper) lateral cartilages. A cleft is between the lower portion of the lateral cartilages to make room for the septal cartilage The lateral cartilages are also connected with the maxillae posteriorly and with the major alar (lower lateral) cartilages inferiorly by means of a fibrous tissue. EXTERNAL NOSE The major alar cartilages, both posses a medial and lateral crus, and are bent forward upon themselves towards the nasal cavity. The lateral and medial crura are connected by a middle crus. The shape of the tip of the nose is determined by the configuration of the two middle crura The rim of the naris is formed by fibrofatty tissue. The same tissue connects the posterior end of the lateral crus to the maxilla and two or three minor alar cartilages lie here. EXTERNAL NOSE The nasal septum divides the vestibule into left and right nasal cavities. The septum is made up of a bony part and a soft mobile cartilaginous part. The main components of the nasal septum are the perpendicular plate of the ethmoid( superior part), the vomer (postero-inferior) and the septal cartilage. The septal cartilage articulates with the edges of the bony septum THE NASAL CAVITIES The nasal cavity extends from the nares, through the external nose and between the bones of the face, as far back as the posterior nasal opennings or choanae (between the posterior borders of the medial pterygoid plates of the sphenoid and the vomer), where the nasal cavity communicates with the nasopharyn It has a lateral, medial, floor and roof wall Courtesy of BRS Anatomy THE NASAL CAVITIES The entire cavity is lined by mucosa except for the vestibule The mucosa is either bound to the perichondrium or periosteum depending on location The inferior two thirds of the nasal mucosa is the respiratory area, and the superior one third is the olfactory area The nasal cavities communicates with the nasopharynx posteriorly, the paranasal sinuses superiorly and laterally, and the lacrimal sac and conjunctiva superiorly. THE NASAL CAVITIES The roof of the nasal cavities is narrow. It is divided into three parts namely frontonasal, ethmoidal, and sphenoidal The floor of the nasal cavities is wider than the roof and is formed by the palatine processes of the maxilla and the horizontal plates of the palatine bone. The medial wall of the nasal cavities is formed by the nasal septum. The lateral walls of the nasal cavities are irregular owing to three bony plates, viz the nasal conchae, which project inferiorly THE NASAL CAVITIES The nasal conchae consists of three bony plates namely the superior, middle, and inferior conchae which are curved inferomedially There is a recess or nasal meatus below each of the bony formations. The nasal cavity is thus divided into 5 meatus: a posterosuperiorly placed spheno-ethmoidal recess, three laterally located nasal meatus (superior, middle, and inferior), and a medially placed common nasal meatus into All other meatus open into the medially placed common nasal meatus THE NASAL CAVITIES The inferior concha is the longest and broadest of the conchae and is formed by the "inferior concha" and covered by a mucous membrane that contains large vascular spaces are expansible. The middle and superior conchae are medial processes of the ethmoid bone. The spheno-ethmoidal recess, lies superoposterior to the superior concha, the sphenoidal sinus, opens into it. The superior nasal meatus is narrow and is the passage between the superior and the middle nasal conchae. The posterior ethmoidal sinuses opens into it. THE NASAL CAVITIES The middle nasal meatus is longer and deeper than the superior meatus, it communicates with the frontal sinus through an anterosuperior placed funnel-shaped opening, the ethmoidal infundibulum. The inferior nasal meatus is horizontal and communicates with passage the nasolacrimal duct, which drains tears from the lacrimal sac The common nasal meatus is the medial part of the nasal cavity, it is between the conchae and the nasal septum, the lateral recesses and meatus open into it. Vasculature and innervation of nasal cavities The arterial supply of the medial and lateral walls of the nasal cavity is from: 1. Anterior ethmoidal artery (from the ophthalmic artery). 2. Posterior ethmoidal artery (from the ophthalmic artery). 3. Sphenopalatine artery (from the maxillary artery). 4. Greater palatine artery (from the maxillary artery). 5. Septal branch of the superior labial artery (from the facial artery). THE PARANASAL SINUSES They are hollows within the bones that form the nasal cavity Consists of the ethmoidal, frontal, maxillary, and sphenoidal sinuses. They communicate with the nasal cavity through ostia Are involved with lightening the weight of the head, and also involved with resonance and phonation PARANASAL SINUS: Ethmoidal sinus Consists of numerous ethmoidal air cells, which are numerous small cavities within the ethmoidal labyrinth between the orbit and the nasal cavity. Its infection may erode through the thin orbital plate of the ethmoid bone (lamina papyracea) into the orbit. Can be subdivided into the following groups: 1. Posterior ethmoidal air cells, which drain into the superior nasal meatus. 2. Middle ethmoidal air cells, which drain into the summit of the ethmoidal bulla of the middle nasal meatus. 3. Anterior ethmoidal air cells, which drain into the anterior aspect of the hiatus semilunaris in the middle nasal meatus. PARANASAL SINUS Courtesy COA PARANASAL SINUS: FRONTAL sinus Lies in the frontal bone and opens into the hiatus semilunaris of the middle nasal meatus by way of the frontonasal duct (or infundibulum). Is innervated by the supraorbital branch of the ophthalmic nerve PARANASAL SINUS: Ethmoidal sinus Is the largest of the paranasal air sinuses and is the only paranasal sinus that may be present at birth. Lies in the maxilla on each side, lateral to the lateral wall of the nasal cavity and inferior to the floor of the orbit, and drains into the posterior aspect of the hiatus semilunaris in the middle nasal meatus. PARANASAL SINUSES: Sphenoidal sinus Is contained within the body of the sphenoid bone. Opens into the sphenoethmoidal recess of the nasal cavity. Is innervated by branches from the maxillary nerve and by the posterior ethmoidal branch of the nasociliary nerve. The transsphenoidal approach gives access to the pituitary gland,, which follows the nasal septum through the body of the sphenoid. PARANASAL SINUS Courtesy of COA DEVELOPMENT OF THE NASAL CAVITY The nasal apparatus involves the appearance of lateral and medial swellings, that form nasnasaal pits which are ectoderm-lined depressions. The nasal pits deepen to form blind sacs, and eventually rupture to form the nostrils. Oronasal membrane initially separates nasal cavities from the oral cavity, but its rupture allows communication between nasal and oral cavities through the primitive choanae. Nasal septum forms as a downgrowth from the medial nasal process. lateral wall is formed as the superior, middle, and inferior conchae DEVELOPMENT OF THE NASAL CAVITY Floor of the nasal cavity is formed by fusion of the medial nasal process (nasal septum) with the palatine processes of the maxilla. Roof of the nose is formed from the lateral nasal processes. Paranasal sinuses develop as diverticula of the lateral nasal wall and extend into the maxilla, ethmoid, frontal, and sphenoid bones. CLINICAL/APPLIED ANATOMY Nasal polyp is an inflammatory finger like projection that develops from the mucosa of the paranasal sinus, which projects into the nasal cavity and may fill the nasopharynx. The most common cause of nasal polyps is allergic rhinitis. Cortisone or nasal steroid sprays that slows the polyp's growth is the medical treatment while polupectomy(, eg endoscopic sinus surgery) is a surgical treatment Rhinitis is an inflammation of the nasal mucous membrane, caused by allergies, and has symptoms of runny nose, nasal itching, nasal congestion, and sneezing. CLINICAL/APPLIED ANATOMY Rhinorrhea (runny nose) is caused by tears draining into the inferior nasal meatus through the nasolacrimal duct. It is often associated with the common cold, hay fever, flu, and allergy, sometimes the drainage from the paranasal sinus is made to empty directly into the nasal cavity. Rhinoplasty is a plastic surgery that changes the shape or size of the nose. Deviation of the nasal septum may obstruct the nasal airway and block the openings of the paranasal sinuse, it can be congenital or acquired CLINICAL/APPLIED ANATOMY Epistaxis is a nosebleed resulting from rupture of the sphenopalatine artery. Nosebleed can also come from nose picking, which tears the veins in the vestibule of the nose. It also occurs from the anterior nasal septum (Kiesselbach area or plexus), where branches of the sphenopalatine (from maxillary), greater palatine (from maxillary), anterior ethmoidal (from ophthalmic), and superior labial (from facial) arteries anastomose. Its treatment includes compression of the nostrils (application of direct pressure to the septal area) and surgical packing. CONCLUSION The nose is the external part of the respiratory system It consists of external nose and the left and rightnasal cavities The paranasal sinuses are hollows in the bones that make up the nose REFERENCES Chung, K W (2015) Board review series Anatomy 8thed Wolters Kluwer: Philadelphia Gray, H (2013). Grays Anatomy. London, England Moore, K L et al (2014) Clinically Oriented Anatomy 7ed Wolters Kluwer: Philadelphia 14th ed Wiley Blackwell: Oxford Sinnatamby, C.S. (2011) Last’s Anatomy: Regional and Applied. 11th Edition, Churchill Livingstone, Elsevier, Saunders,