(22) Nasal Cavities, Inside of Pharynx, Palate

functions of the nasal cavities

- Olfaction

- Respiration

- Dust filtration

- Air humidification

- Receptacles for secretions from nasal mucosa and tears from nasolacrimal duct

roof of nasal cavity

nasal, frontal, ethmoid, and sphenoid bones

floor of nasal cavity

palatine (horizontal plate) & maxilla (palantine process) bones

medial border of nasal cavity

nasal septum

lateral border of nasal cavity

maxilla, lacrimal, ethmoid, inferior nasal concha, and palatine

nasal septum

partition made of bones (primarily vomer & ethmoid, which are both unpaired) & septal cartilage separating the right and left nasal cavities

Inferior orbital fissure

hole in the orbit floor between maxilla and greater wing of sphenoid that allows V2 and arteries to reach the superficial face & nasal cavities

piriform aperture/anterior nasal aperture

single bony anterior opening to the 2 nasal cavities between maxilla and nasal bones

choana/posterior nasal aperture

posterior opening from the nasal cavity to the nasopharynx

nares

nostrils, which are separated by the nasal septum

the shape of the nose largely depends on

cartilage

nasal cartilages

1. Lateral cartilage

2. Alar cartilage

3. Septal Cartilage

lateral cartilage

strip of cartilage on either side of the bridge of the nose

alar cartilage

cartilage that shape the nares medially (lateral is fat)

septal cartilage

Cartilage forming part of the anterior part of the nasal septum.

perpendicular plate of ethmoid bone

part of the ethmoid bone that forms superior part of nasal septum

nasopalatine groove

groove on lateral surface of vomer where nasopalatine nerve and branches of sphenopalatine artery run

Deviated Septum

Abnormal positioning of the septum in which vomer and/or septal cartilage is out of midline

orbital plate/Lamina papyracea

paper-thin wall of ethmoid bone between orbit and nose. vulnerable to shattering if one takes a blow to the head.

sphenopalatine foramen

hole that allows passage of some nerves & blood vessels into the nasal cavity. meeting point of palatine perpendicular plate & sphenoid medial pterygoid plate.

Conchae (turbinates)

very thin bones of the lateral wall of the nasal cavity. superior, middle, inferior.

-superior & middle are part of the ethmoid bone

-inferior is its own separate bone

Sphenoethmoidal recess

most superior space in the lateral wall of the nasal cavity between the anterior sphenoid & the superior nasal concha

superior meatus

space in the lateral wall of the nasal cavity below the superior nasal concha

middle meatus

space in the lateral wall of the nasal cavity below the middle nasal concha

inferior meatus

space in the lateral wall of the nasal cavity below the inferior nasal concha

Paranasal sinuses

paired spaces within the skull bones. frontal, ethmoid, sphenoid, maxillary; named for the bone they are in.

Frontal sinus

paranasal sinus located in the frontal bone.

maxillary sinus

paranasal sinus located in the maxilla, between the orbit & upper teeth

-roof is the orbit

-floor is the alveolar process with tooth roots

sphenoid sinus

paired paranasal sinus located in the body of the sphenoid near the pituitary

ethmoid sinus/ethmoid air cells/labyrinth

paranasal sinus located on either side of the ethmoid bone. divided into pockets.

-Medial to orbit

Nasal Vestibule

part of the nasal cavity that is immediately deep to nares & is lined with skin (everything else is lined with epithelium)

nasal mucosa

Epithelium that lines the nasal cavity & produces mucus (about a quart per day). Contains cilia that moves mucus toward openings to be drained into nasopharynx & swallowed.

Ethmoid Bulla

bulge of ethmoid bone underneath the middle conchae that projects into the middle meatus

semilunar hiatus

space in middle meatus that contains openings to the frontal & maxillary sinuses

Ostium of maxillary sinus

centrally-located opening to the maxillary sinus that is accessible through the semilunar hiatus

tears drain from

nasolacrimal duct to inferior meatus

drainage of frontal sinus

frontonasal duct -> semilunar hiatus -> middle meatus

drainage of anterior ethmoidal cells

Semilunar hiatus to middle nasal meatus

drainage of middle ethmoidal cells

ethmoidal bulla to middle nasal meatus

drainage of posterior ethmoidal cells

directly to superior meatus

drainage of sphenoid sinus

sphenoethmoidal recess

drainage of maxillary sinus

ostium -> semilunar hiatus -> middle meatus

anterior cranial fossa is located

superior to nasal cavity

Nerves of Nasal Cavity

1. Olfactory Nerve (CN I) - special sense of smell

2. Ophthalmic Nerve (CN V1) - somatic sensory

3. Maxillary Nerve (CN V2) - somatic sensory

4. Facial Nerve (CN VII) - parasympathetic for mucus production

5. Postganglionic sympathetic fibers - blood vessels

Olfactory Mucosa

mucosa that lines the superior region of the nasal cavity and contains olfactory nerve endings (therefore only the areas covered by this are sensitive to smell)

-1/3 of total nasal mucosa

Respiratory Mucosa

2/3 of total nasal mucosa , which contains somatic sensory, parasympathetic, & sympathetic nerves

Frontal & Ethmoid Sinuses receive somatic sensation from

branches of V1

Sphenoid Sinus receives somatic sensation from

branches of both V1 and V2

Maxillary Sinus receives somatic sensation from

branches of V2

pterygopalatine fossa

space in the deep face deep to the infratemporal fossa.

-CN V2 enters posteriorly & laterally from foramen rotundum, & emerges anteriorly in the orbital floor as the infraorbital nerve running with the infraorbital artery & vein

-Maxillary artery enters laterally from pterygomaxillary fissure & emerges medially as the sphenopalatine artery running with the nasopalatine nerve

-Nerve of pterygoid canal enter posteriorly & medially from the pterygoid canal

-Floor contains greater & lesser palatine foramina

branches of V2 in nasal cavity

1. Infraorbital nerve

2. Greater palatine nerve

3. Lesser palatine nerve

3. Superior alveolar nerve

4. Nasopalatine nerve

infraorbital nerve

branch of V2 that passes through the infraorbital foramen

Greater palatine nerve

branch of V2 that passes through the greater palatine foramen & provides sensory innervation to the hard palate, as well as parasympathetics from CN VII for glands of the hard palate mucosa

lesser palatine nerve

branch of V2 that passes through the lesser palatine foramen & provides sensory innervation to the soft palate, as well as parasympathetics from CN VII for glands of the soft palate mucosa

Superior alveolar nerves

branch of V2 that runs in the maxillary sinus & provides sensory innervation to the upper teeth

Nasopalatine nerve

branch of V2 that passes through the sphenopalatine foramen to the nasal septum, & then through the incisive canal to the hard palate. provides sensory innervation to the hard palate & nasal septum

anterior ethmoidal nerve

branch of V1 that provides sensory innervation to the nasal septum & lateral nasal wall

greater petrosal nerve

Branch of CN VII that carries preganglionic parasympathetics fibers that join the deep petrosal nerve to run along V2 at the nerve of the pterygoid canal

deep petrosal nerve

Postganglionic sympathetic fibers that run along the interal carotid artery to get to the head, & then jump off to join the greater petrosal nerve to run along V2 at the nerve of the pterygoid canal

nerve of the pterygoid canal

combination of postganglionic sympathetics from the deep petrosal nerve & preganglionic parasympathetics from the greater petrosal nerve that runs to the pterygopalatine ganglion

Pterygopalatine Ganglion

Ganglion suspended by CN V2 but used by CN VII for parasympathetic fibers to synapse and then get to the lacrimal gland & mucosa of nasal cavity, sinuses, & hard/soft palates via V1 & V2 branches.

-Sympathetic fibers also pass through on their way to blood vessel

blood comes to the nasal cavities as indirect branches of

ICA & ECA

Sphenopalatine artery

terminal branch of maxillary artery that passes through the sphenopalatine foramen & then runs down the nasal septum & through the incisive canal to supply the hard palate

incisive canal

passageway between the 2 front teeth

Descending palatine artery

Terminal branch of the maxillary artery that runs posterior to conchae within the greater palatine canal. Branches into the lesser palatine artery & greater palatine artery near the palate.

Lesser palatine artery

Branch of the descending palatine artery that passes through the lesser palatine foramen (with the lesser palatine nerves) & supplies the soft palate.

greater palatine artery

Branch of the descending palatine artery that passes through the greater palatine foramen (with the greater palatine nerves) & supplies the hard palate

anterior & posterior ethmoidal arteries

branches of the ophthalmic artery that supply the nasal cavity

submucosal venous plexus

Very small network of veins that drain blood from the nasal cavities to the facial and ophthalmic veins. Also warms air entering the nasal cavity that ultimately reaches the lungs.

-Located in the "danger area" of the face due to communication with the cavernous sinus

anterior nasal septum

common area of nosebleeds due to anastomoses of several arteries

anterior nosebleeds

Less serious nosebleeds that heal quickly. Bleeding is from veins.

posterior nosebleeds

More serious nosebleeds that can be life threatening. Bleeding is from arteries, which can result in quarts of blood loss within hours.

location of nasopharynx

posterior to choanae, from skull base to soft palate

location of oropharynx

posterior to palatoglossal fold & root of tongue, from soft palate to epiglottis

location of laryngopharynx

posterior to larynx, from epiglottis/hyoid bone to cricoid cartilage (C6 level)

hard palate

Anterior part of the palate consists of maxilla and palatine bones covered by cartilage. floor of nasal cavity & roof of oral cavity.

palatine process

part of the maxilla that meets the horizontal plate of the palatine

horizontal plate

part of the palatine that meets the palatine process of the maxilla

scaphoid fossa

space between pterygoid plates at base of skull

hamulus

hook-shaped projection on the medial pterygoid plate

soft palate

posterior portion of the palate consisting of muscles covered by mucous membrane

Fauces

opening between oral cavity and oropharynx. contains palatopharyngeal and palatoglossal folds, palatine tonsils, & uvula.

"fold" refers to a

fold of epithelium covering undissected muscle

palatoglossal fold

A fold of tissue anterior to the palatine tonsil that covers the palatoglossus muscle

palatopharyngeal fold

A fold of tissue posterior to the palatine tonsil that covers the palatopharyngeal muscle

palatine tonsils

tonsils that are located on either side of the throat medial to the superior constrictor & between the palatoglossal fold & palatopharyngeal fold

muscles of the soft palate

1. Palatopharyngeus

2. Palatoglossus

3. Uvula

4. Tensor veli Palatini

5. Levator Veli Palatini

Palatopharyngeus muscle

muscle that runs from the hard palate & palatine aponeurosis to the thyroid cartilage & pharynx. Functions to elevate the pharynx & larynx in swallowing & speaking.

-Innervated by vagus nerve (CN X)

palatoglossus muscle

muscle that runs from the palatine aponeurosis to the tongue. Functions to elevate the posterior tongue in swallowing.

-Innervated by vagus nerve (CN X)

uvula

Muscle in the midline of the soft palate. Functions to close the nasopharynx in swallowing, & plays a role in speech.

-Innervated by vagus nerve (CN X)

Tensor veli Palatini

Muscle that runs from the scaphoid fossa of sphenoid bone to the palatine aponeurosis after its tendon winds around the hamulus. Functions to tense the soft palate & open the auditory tube during swallowing.

-Innervated by CN V3

Levator Veli Palini

Muscle that runs from the cartilage of Eustachian tube and petrous temporal bone to the palatine aponeurosis. Functions to elevate the soft palate & close off the nasopharynx during swallowing.

-Innervated by vagus nerve (CN X)

Epiglottis

A flap of tissue that seals off the larynx during swallowing

Aditus/Inlet of larynx

Entrance to the larynx at the end of the pharynx

piriform recess

Small depression on either side of the laryngeal inlet where objects may get stuck.

-Bordered laterally by the thyroid cartilage, posteriorly by the inferior constrictor, & medially by the larynx