Nose 1

WINDSOR UNIVERSITY

SCHOOL OF MEDICINE

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THE NOSE

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REGION.

Dr.Vishal  Surender .MD. 

THE NOSE

part of the respiratory tract superior to the hard palate and contains the peripheral organ of smell. COMPONENTS External Nose Nasal Cavity- divided in to right and lf by nasal septum and each nasal cavity further divided in to olfactory and respiratory area>  FUNCTIONS Warm and moisten the inspired air Clean the inspired air by trapping dust particles through the vibrissae and lining respiratory epithelium

EXTERNAL NOSE

varies considerably in size and shape, mainly because of differences in the nasal cartilages. The dorsum of the nose extends from its superior angle, the root , to the apex (tip) of the nose. The inferior surface of the nose is pierced by two piriform openings, the nares (nostrils, anterior nasal apertures), which are bound laterally by the alae (wings) of the nose and separated from each other by the nasal septum. The external nose consists of bony and cartilaginous parts Superiorly – bone nasal bones frontal processes of the Maxilla nasal part of the frontal Bone Inferiorly - hyaline Cartilage septal cartilages major and minor alar cartilages

NASAL CAVITY extends from the nostrils anteriorly to the choanae Posteriorly divided into right and left halves by the nasal septum

Subdivisions of nasal cavity Vestibule

Dilatation inside nostril lined by skin with hairs to filter incoming Air

Olfactory region

Upper third of nasal cavity lined with olfactory mucosa

Respiratory region

Lower two thirds of nasal cavity lined with highly vascular, glandular respiratory mucosa to warm and humidify air

nasal mucosa Alternate breathing .

elationships of nasal cavity Roof

Related anteriorly to anterior cranial fossa and posteriorly to body of sphenoid with sphenoidal sinuses

Floor

Hard palate separating nasal cavity from oral cavity

Medial wall

Formed by nasal septum of septal cartilage , perpendicular plate of ethmoid , and vomer , and the nasal crests of the maxillary and palatine bones.

Lateral wall

Complicated structure formed by parts of lacrimal, ethmoid, maxillary, palatine, sphenoid, and inferior nasal concha bones

Deviation of the nasal septum Deviation of the nasal septum may obstruct the nasal airway and block the openings of the paranasal sinuses . Ashley Tisdale

Nasal trauma and developmental defects are the most common causes.

Cocaine abuse can be

diagnosed by looking at the nasal septum which is usually perforated.

Lateral wall of nasal cavity Uneven because of nasal conchae, Superior and middle nasal conchae Processes of ethmoid bone Inferior nasal concha Separate bone

Lateral wall of nasal cavity

The nasal conchae divide the nasal cavity into four passages

Sphenoethmoidal recess receives the opening of the sphenoidal air sinus

Superior meatus

Receives opening of posterior ethmoidal air cells

Middle meatus and

Infundibulum, ethmoidal bulla*

semilunar hiatus Receives openings of frontal and maxillary sinuses and anterior and * middle ethmoidal air cells

Inferior meatus

Receives opening of nasolacrimal duct

BLOOD SUPPLY OF THE NASAL CAVITY Arterial - mainly from branches of the maxillary artery

 sphenopalatine artery branch of the maxillary artery ; enters the nasal cavity through the sphenopalatine foramen  anterior and posterior ethmoidal arteries - from ophthalmic artery  alar and septal branches of the superior labial branch of the facial Artery

Veins - form a rich plexus in the submucosa; accompany the corresponding arteries

LYMPH DRAINAGE OF THE NASAL CAVITY Vestibule submandibular nodes Rest of nasal cavity deep cervical nodes

Epistaxis ( nosebleed )

most often occurs from the anterior nasal septum ( Kiesselbach's area ), where branches of the sphenopalatine , anterior ethmoidal , greater palatine , and superior labial ( from facial) arteries converge.

Foreign bodies in the nasal cavity Foreign bodies in the nasal cavity are common in children. Folded, shelf-like conchae make impaction and retention of balloons, peas, small toys relatively easy Symptoms Thick yellow nasal discharge, foul odor from the nose, noisy breathing, itching, nasal pain, recurrent nosebleeds, headaches.

NERVE SUPPLY OF THE NASAL CAVITY 1 . Special sensation : olfactory nerves ( CN I )  2 . General sensation : anterior part anterior ethmoidal nerve (from nasociliary branch of ophthalmic nerve CN V1 ) -Posterior part nasal, nasopalatine, and palatine branches of the pterygopalatine ganglion and internal nasal branch of infraorbital nerve (from maxillary nerve CN V2 )

NERVE SUPPLY OF THE NASAL CAVITY 3 . Autonomic : Preganglionic parasympathetic innervation to glands derived from facial nerve ( CN VII ) with postganglionic fibers from cell bodies in pterygopalatine ganglion distributed through branches of ganglion and

maxillary nerve

Postganglionic sympathetic innervation to blood vessels from cell bodies in superior cervical ganglion distributed through branches of maxillary nerve and pterygopalatine ganglion and also through perivascular plexuses

PARANASAL SINUSES

 Develop as outgrowths of nasal mucosa into bones surrounding nasal cavity  Innervated by maxillary and ophthalmic divisions of CN V  Reduce weight of skull, serve as resonating chambers for sound production, and increase surface area for warming and humidifying inspired air  Communicate with the nasal cavity through small apertures or openings

Maxillary sinus

Largest of paranasal sinuses and already present at birth Located within body of maxilla lateral to nasal cavity and inferior to orbit Drains into middle meatus through semilunar hiatus Variably related to roots of maxillary molars

Maxillary sinusitis In maxillary sinusitis , the sinus accumulates mucus. Because the ostium of the maxillary sinus is well above the level of its floor, its drainage is inefficient, particularly when inflamed. To facilitate drainage, an accessory opening may be created surgically , often into the inferior meatus . Only a thin layer of bone and just mucous membrane may separate the roots of the maxillary teeth from the sinus cavity , and sinusitis frequently produces a toothache . If only a thin layer of bone covers the roots of the molars, extraction may create a fistula between the sinus

Sphenoidal sinus

Lies within body of sphenoid and is divided into left and right sinuses by oblique bony septum , each draining into sphenoethmoidal recess Supplied by maxillary and ophthalmic nerves and sphenopalatine and ophthalmic arteries

Important relationships : Superiorly : pituitary gland in hypophyseal fossa and optic chiasma and nerves Inferiorly : nasal cavity and nasopharynx Laterally : cavernous sinus and internal carotid artery Posteriorly : brainstem in posterior cranial fossa

Sphenoiditis Relationships of the sphenoidal sinus are clinically important ; because of potential injury during pituitary surgery and the possible spread of infection . Infection can reach the sinuses through their ostia from the nasal cavity or through their floor from the nasopharynx . Infection may erode the walls to reach the cavernous sinuses, pituitary gland , optic nerves , or optic chiasma

Ethmoidal sinus Related : Medially - to nasal cavity , Laterally - to orbit , Superiorly - to anterior cranial fossa Consists of anterior , middle , and posterior ethmoidal air cells Anterior ethmoidal cells : open into middle meatus ( anterior ethmoidal nerve and artery) Middle ethmoidal cells : open into middle meatus ( anterior ethmoidal nerve and artery) Posterior ethmoidal cells : open into superior meatus and share nerve and blood supply with sphenoidal sinus

Ethmoiditis Infection in the ethmoidal sinuses can erode the medial wall of the orbit, resulting in orbital cellulitis that can spread to the cranial cavity.

Frontal sinus Paired sinus of highly variable size in squamous and orbital parts of frontal bone that drains by infundibulum into middle meatus Related posteriorly to anterior cranial fossa and interiorly to orbit Supplied by supratrochlear and supraorbital nerves and arteries

Frontitis Frontal sinusitis is usually accompanied by maxillary sinusitis because of the close relationship of the ostia in the middle meatus. Frontal sinusitis may erode the thin bone of the anterior cranial fossa, producing meningitis and / or brain abscess. Despite antibiotic therapy, sinusitis with intracranial spread is a significant source of morbidity and mortality.