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Anatomy of nose By: Elaf almutairi, Esraa abdulrahman and Ghada abu jamea Nose Origin: Originates from the nasofrontal process during 4th to 8th week of IU life. Consists of : - External nose. - Nasal cavity. The external nose : Is a pyramidal projection of face . - Tip - Root - Dorsum - Ala of nose bounding inferiorly a pair of nostrils - External nose The external nose has two elliptical orifices called the naris (nostrils) , which are separated from each other by the nasal septum. The lateral margin, the ala nasi is rounded and mobile. External nose Osteocartilaginous framework: Bony pyramid – upper 1/3rd it is responsible for the height of the nose. It provides the support for the upper portion of the nose. Cartilaginous part – lower 2/3rd (Upper & lower cartilaginous vault) The greater alar cartilage and the lesser alar cartilages give your tip and nostrils their shape. Blood Supply of Nose The skin of the external nose is supplied by branches of the ophthalmic and the maxillary arteries The skin of the ala and the lower part of the septum are supplied by branches from the facial artery which originate from external carotid artery. Nerve Supply of the External Nose The infratrochlear and external nasal branches of the ophthalmic nerve (CN V) and the infraorbital branch of the maxillary nerve (CN V) for general sensation. Internal nose Vestibule of nose Nasal cavity divided into right & left halves by the nasal septum each half has a: Lateral wall Medial wall Roof Floor LINING MEMBRANE OF INTERNAL NOSE Vestibule: Lined by skin containing hair, hair follicles, sebaceous glands. Olfactory region: Mucous membrane. Respiratory region: Mucous membrane shows varible thickenings. The Lateral Walls of Nasal Cavity Marked by 3 projections: 1. Superior concha (turbinate). 2. Middle concha (turbinate). 3. Inferior concha (turbinate). Lateral wall The cavity below each concha is called a meatus. The small space above the superior concha is the sphenoethmoial (suprameatal) recess. meatus Sphenoethmoidal recess The Lateral Walls of Nasal Cavity 1. Inferior meatus: nasolacrimal duct. 2. Middle meatus: • Maxillary sinus. • Frontal sinus. • Anterior ethmoid sinuses. 3. Superior meatus: posterior ethmoid sinuses. 4. Sphenoethmoidal recess: sphenoid sinus. Medial wall Osteo-cartilaginous partition between the two nasal cavities called nasal septum. Formed by: 1. Septal cartilage (anterior). 2. Perpendicular plate of ethmoid bone (superior). 3. Vomer (inferior). Septal Cartilage Vomer Roof Narrow & formed (anteroposteriorly) by the: 1. Nasal bone & cartilage 2. Frontal bone. 3. Cribriform plate of ethmoid bone 4. Body of sphenoid. •Floor •Ant. 3/4th formed by palatine process of the maxilla •Post. 1/4th formed by the palatine bone. Blood supply Blood supply of lateral wall INTERNAL CAROTID SYSTEM: 1. Anterior ethmoidal. 2. Posterior ethmoidal } Branches of ophthalmic artery. EXTERNAL CAROTID SYSTEM: 1. Posterior lateral nasal Branches → From sphenopalatine artery. 2. Greater palatine artery → From maxillary artery. 3. Nasal branch of anterior superior dental → From infraorbital branch of maxillary Artery. 4. Branches of facial artery to nasal vestibule. Blood Supply to the Nasal Cavity 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(little area). The submucous venous plexus is drained by veins that accompany the arteries. Sphenopalatine a. Maxillary a. Nerve Supply of the 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 (V1) and the maxillary division (V2) of the trigeminal nerve. Nerve Supply of the Nasal Cavity CN I – Olfactory Nerves (SVA) Anterior ethmoidal branch of V1 Cut nasopalatine branch of V2 to septum Posterior nasal branches of V2 Lymph Drainage of the Nasal Cavity The lymph vessels draining the vestibule end in the submandibular lymph nodes. The remainder of the nasal cavity is drained by vessels that pass to the upper deep cervical nodes. The paranasal sinuses are cavities found In the inferior of the maxilla, frontal, sphenoid , And ethmoid bones. They are lined with mucoperiosteum and filled with air. They communicate with the nasal cavity through relatively small apertures. Maxillary sinus Pyramid in shape 15cc Capacity. Paired and symmetric Located within the body of the maxilla behind the skin of the cheek. The roof is formed by the floor of the orbit and the floor related to the roots of the 2nd premolar and 1st molar teeth. • The maxillary sinus opens into the middle meatus of the nose. • It appear radiologically after 5 months from delivery, at age of 15 it reach full capacity. • • • • Frontal sinuses Paired rarely symmetrical, 7cc capacity. Contained within frontal bone Separated from each other by a bony septum . Each sinus is roughly triangular Extending upward above the medial end of the eyebrow and backward into the medial part of the roof of the orbit. • Opens into the middle meatus • • • • • Sphenoidal sinuses • Lie within the body of the sphenoid bone • Below Sella turcica (extends between dorsum sellae and post clinoid processes) • Opens into the sphenoethmoidal recess above the superior concha. • Laterally related to ophthalmic nerve , internal carotid artery So it’s sensitive area for surgeon when they need to remove pituitary gland . Ethmoidal sinuses • They are anterior, and posterior • They are contained within the ethmoid bone, between the nose and the orbit • Anterior and middle (drains into middle nasal meatus) • Posterior(drain into superior nasal meatus) • Separated from the orbit by a thin plate of bone so that infection can readily spread from the sinuses into the orbit. Functions of the nose: 1- Respiration. 2- Air-conditioning of inspired air. 3- Vocal resonance. 4- Nasal reflex function. 5- Protection of lower airway. 6- Olfaction. 1.Respiration: Inspiration: Very little air passes through inferior meatus or olfactory region of nose. Expiration: The entire air current is not expelled directly through the nares, some goes through inferior and middle turbinates and this ventilates the sinuses through the ostia. Asymmetrical Congestive Response (The Nasal Cycle): Normal physiological congestion/decongestion cycle alternating between nasal sides every 2–7 hours. 2. Air conditioning of inspired air: 1. Filtration and Purification: The nasal vibrissae, the mucus membrane and the nasal mucus all help in trapping small particles. 2. Temperature control: cavernous venous spaces or sinusoids in the mucosal membrane help in reducing or increasing temperature of inspired air to match body temperature. 3. Humidification: The mucous membrane adjusts the relative humidity of the inspired air to 75% or more. 3. Protection of lower airway: Mucociliary mechanism: the mucus blanket; formed of secretions of goblet cells and secretory glands lies on cilia and carries microorganisms to the nasopharynx to be swallowed. Enzymes and immunoglobulins: lysosymes, IgA and IgE secreted in nasal cavity kill bacteria and provide immunity. sneezing: protective reflex. Foreign particles which irritate nasal mucosa are expelled by sneezing. 4.Vocal Resonance: When the nose is blocked the speech becomes denasal. 5. Nasal Reflexes: Nasal function is closely related to pulmonary functions through nasobronchial and nasopulmonary reflexes. (secretion of salaiva, sneezing, nasal obstruction and pulmonary resistance, etc.) 6. Olfaction: Olfactory Pathways: Peripheral processes of olfactory cells act as sensory receptors for odorous substances while central processes are grouped into olfactory nerves which pass through the cribriform plate of ethmoid and end in the mitral cells of the olfactory bulb. Smell is then carried through axons of mitral cells of olfactory tract to the prepyriform cortex and the amygdaloid nucleus where it reaches consciousness. Sense of smell can be tested by asking the patient to smell common odours such as lemon, peppermint, rose, garlic or cloves from each side of the nose separately, with eyes closed. Function of sinuses: Ventilation of sinuses is paradoxical; they are emptied of air during inspiration and filled with air during expiration. 1. Air-conditioning of the inspired air. 2. Resonance to voice. 3. Thermal insulators to protect the delicate structures in the orbit and the cranium. 4.To lighten the skull bones. 5.To provide extended surface for olfaction. 6.Immunologic defence against microbes. 7. Protect brain against injury by acting as buffers. Thank you