Nose and Nasal Cavity

• Pyramidal shape

• Nares (nostrils)

• Alae of the nose

• Nasal septum

• Nasal vestibule (lined with skin and hairs)

• Dorsum, root, and apex of the nose

Parts of the external nose (general structure)

Respiratory area (inferior 2/3)

• Lined with respiratory epithelium

• Warms air

• Traps particles

Olfactory area (superior 1/3)

• Lined with olfactory epithelium

• Contains receptors for smell

nares; nasal vestibule; nasal mucosa

Air enters through the _____ into the _____, then it transitions to _____

choanae

The nasal cavity opens to nasopharynx via _____

Duplex house comparison

General layout of the nasal cavity; “mirror image cavities”

• Frontal and nasal bones

• Cribriform plate (ethmoid bone)

• Sphenoid, vomer, palatine bones

Roof of nasal cavity

• Hard palate

• Palatine process (maxilla) and horizontal plates (palatine)

Floor of nasal cavity

Nasal septum (cartilaginous and bony parts)

Medial wall of nasal cavity

• Ethmoid (major upper part)

• Maxilla (frontal process)

• Lacrimal bone

• Inferior concha

• Palatine bone (perpendicular plate)

• Sphenoid (medial pterygoid plate)

Lateral wall of nasal cavity

Spheno-ethmoidal recess

Drains sphenoidal sinus

Superior meatus

Drains posterior ethmoidal air cells

Ethmoidal infundibulum

Drains:

• Frontal sinus

• Anterior ethmoidal air cells

Semilunar hiatus

Drains maxillary sinus

Ethmoidal bulla

Drains middle ethmoidal air cells

Inferior meatus

Drains nasolacrimal duct (tears)

Respiratory mucosa

Lining of paranasal sinuses

Frontal sinuses

Located behind root of nose

Maxillary sinuses

• Largest sinus; located in maxillary bone

• Pyramid-shaped

Ethmoid sinuses

Anterior, middle, and posterior ethmoidal air cells

Sphenoid sinuses

• Located in sphenoid bone

• Variable shapes, cube-like

• Sphenopalatine artery (from maxillary)

• Anterior & posterior ethmoidal arteries (from ophthalmic)

Arteries supplying both walls of the nose

• Greater palatine artery

• Septal branch of superior labial artery

Additional septum arteries supplying the nose

Kiesselbach’s area

Common site of nosebleeds

Anterior ethmoidal artery

Gives off the external nasal branches to the external nose

Superior labial artery

Gives off the septal branches to the external nose

Infraorbital artery

Gives off the nasal branches to the external nose

Facial artery

Gives off the lateral nasal branches to the external nose

Submucosal venous plexus

Blood from the nose drains through a network called the _____

Sphenopalatine, facial, ophthalmic veins

Main venous drainage of the nose

Internal jugular vein

Facial vein drains into _____

Pterygoid plexus, cavernous sinus

The veins anastomose with the _____

Danger triangle

Risk of intracranial infection spread

CN I (Olfactory)

Special sensory innervation of the nose

CN V (Trigeminal)

General sensory innervation of the nose

CN V1 (Ophthalmic), CN V2 (Maxillary)

Two branches of CN V that supply the nose

Anterior/posterior ethmoidal nerves (Nasociliary nerve from CN V1)

Innervates nasal cavity, sinuses

External nasal nerve (Nasociliary nerve from CN V1)

Innervates skin of nose

Infratrochlear nerve (Nasociliary nerve from CN V1)

Innervates root, dorsum of external nose

Nasopalatine nerve (from CN V2)

Innervates nasal septum + anterior maxillary teeth

Greater palatine nerve

Innervates overlying mucosa (lateral wall of nose)

Infraorbital nerve

Innervates lateral part of external nose, alae

Supraorbital nerve (V1)

Frontal sinus innervation

Infraorbital & superior alveolar nerves (V2)

Maxillary sinus innervation

Anterior/posterior ethmoidal, orbital branches from pterygopalatine ganglion

Ethmoid sinus innervation

Posterior ethmoidal (V1), Orbital branches (V2)

Innervates ethmoidal cells & sphenoid sinus

Pharynx

Where air & food passageways meet

Inferior conchae

Concha that is an individual bone

Warms air

Function of nasal conchae

Opening of nasolacrimal duct

Drains lacrimal fluid from lacrimal sac

Pterygoid plexus

The sphenopalatine vein drains to _____

Facial vein

The superior labial vein drains to _____

Ophthalmic vein ; cavernous sinus

Anterior & posterior ethmoidal veins drain into _____, then into _____

Anterior ethmoidal nerve

Terminates as external nasal nerve

Maxillary sinus

Which sinus can be perforated during extraction of maxillary molars/canine?

Nasopalatine nerve

Passes through sphenopalatine foramen and incisive foramen