The Nose and Paranasal Sinuses Anatomy of the Nose

• External Nose: • Pyramidal • Osteocatilaginous framework, covered with muscles and skin.

• Bony Part: • Upper 1/3 • 2 nasal bones, nasal process of frontal bone, frontal processes of maxillae.

• Cartilaginous part: • Upper lateral Cartilage: it’s lower free edge forms part of the nasal valve. • Lower lateral cartilage (alar cartilage): U-shaped, Medial and lateral crura. • Lesser alar (Sesamoid) cartilage: 2 or more • Septal cartilage Anatomy of the Nose

• Internal Nose:

• Divided into left and right nasal cavities by the nasal septum • Each nasal cavity communicates with the exterior through the nasris or nostril, and with the nasopharynx through the posterior nasal aperture or the choana. • Each nasal cavity consists of skin lined portion (the vestibule) and a mucosa lined portion (the nasal cavity proper).

Anatomy of the Nose • Internal Nose: • Vestibule: • Anterior and inferior part of the nasal cavity • Lined by skin, contains sebaceous glands, hair follicles, hair (vibrissae) • Nasal valve

• Nasal Cavity Proper: • Lateral nasal wall: 3 turbinates, with 3 corresponding meati (space bellow the turbinate) • Inferior meatus: drains the nasolacrimal duct. • Middle meatus: drains the maxillary, frontal, anterior ethmoidal sinuses • Superior meatus: drains the posterior ethmoidal sinuses. • The nasal septum (medial wall): • Bone: vomer, perpendicular plate of ethmoid bone, maxillary crest, palatine bone • Cartilage: quadrangular cartilage • Roof: nasal bone anteriorly, cribriform plate of ethmoid in the middle, body of sphenoid posteriorly. • Floor: palatine process of maxilla, palatine bone.

Lateral Nasal Wall Nasal Septum

• Lining of the nose: • Vestibule: skin • Olfactory area • Respiratory region: pseudostratified ciliated columnar epithelium, erectile, highly vascular. • Blood supply: • Internal and external carotid arteries. • Nasal septum: • ICA: anterior and posterior ethmoidal arteries. • ECA: sphenopalatine artery, greater palatine artery, superior labial artery. • Lateral wall: • ICA: anterior and posterior ethmoidal arteries. • ECA: sphenopalatine artery, greater palatine artery, maxillary artery, facial artery.

• Kiesselbach’s plexus (Little’s area) Confluence of vessels along the anterior nasal septum where the septal branch of sphenopalatine artery, anterior ethmoidal artery branches, greater palatine artery, and septal branches of superior labial artery anastomose

• Woodruff’s plexus (naso -nasopharyngeal plexus) Anastomosis of posterior ethmoid, sphenopalatine, and ascending pharyngeal arteries along posterior lateral nasal wall inferior to the inferior turbinate

Venous Drainage

Sphenopalatine vein drains via sphenopalatine foramen into pterygoid plexus. Ethmoidal veins drain into superior ophthalmic vein. Venous system is valveless Anterior facial vein drains through common facial vein to internal jugular vein; also communicates with cavernous sinus via ophthalmic veins Angular vein drains external nose via ophthalmic vein to cavernous sinus.

Lymphatic Drainage

Anterior portion of nose drains toward external nose in the submandibular nodes. Posterior portion into upper deep cervical nodes.

Anatomy

• External nasal valve (nasal vestibule) formed by:

• columella • Nasal rim (caudal border of the lower lateral cartilage). • nasal floor • The nasalis muscle dilates this portion during inspiration.

• Internal nasal valve formed by:

• Nasal septum • caudal border of the Upper lateral Cartilage • head of the inferior turbinate

Paranasal sinuses Paranasal sinuses

• Pseudostratified columnar ciliated epithelium with goblet cells • Nasal cilia beat 10-20 times/sec at room temp • Functions; Humidification, Vocal resonance, Mucus production, Absorbs shock to the head, Regulation of intranasal pressure • The ethmoid and the maxillary sinuses; Present at birth

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