Nose and Sinuses

Question 1

External Nose

Answer 1

• Pyramidal, external part of nasal cavity (tip of nose is apex of pyramid) • Includes nasal bones and parts of frontal and maxillary bones • Includes parts of alar cartilages and part of septal cartilage • Has external openings (nares)

Question 2

External naris

Answer 2

• Paired, oval, external openings of nasal cavity separated by the nasal septum • Walls supported by cartilage alar and septal cartilages Also known as: • “Nostril” Comment: • Naris widened further by actions of related facial muscles

Question 3

Ala of nose

Answer 3

Lateral wall of nostril; composed of skin and alar cartilages

Question 4

Frontal Sinus

Answer 4

Located on frontal bone, superior to orbit Description: • Paired, mucous membrane-lined cavity • One of paranasal air sinuses Comment: • Drains into middle nasal meatus via frontonasal duct • Common site of sinus infection • Contributes to voice resonance • Paranasal sinuses include: frontal, maxillary, and sphenoidal sinuses, and ethmoidal cells (sinus)

Question 5

Frontal Lobe

Answer 5

Frontal lobe Located on anterior portion of cerebral hemisphere Description: • Extends from anterior pole of brain to central sulcus • Contains precentral gyrus Function: • Controls voluntary motor activity • Higher mental processing • Emotional behavior • Speech output (i.e., Broca’s area - usually in left hemisphere)

Question 6

Frontonasal duct

Answer 6

Located between frontal sinus and nasal cavity Description: • Bony channel • Superior opening in frontal sinus • Continues in middle nasal meatus as ethmoidal infundibulum

Question 7

Perpendicular plate of ethmoid bone

Answer 7

Description: • Thin, vertical projection of ethmoid in nasal cavity Comment: • Forms superior part of nasal septum • Articulates with vomer and nasal septal cartilage

Question 8

Middle nasal meatus

Answer 8

Location: • Inferior and lateral to middle nasal concha Description: • Narrow space that contains openings of anterior and middle ethmoidal air cells, and maxillary and frontal sinuses • Contains ethmoidal bulla and semilunar hiatus Function: • Nasal mucosa that lines meatus warms, filters, and humidifies inhaled air

Question 9

Middle Nasal Concha

Answer 9

Located in lateral wall of nasal cavity Description: • Shelf-like projection of ethmoid bone covered by thick mucosa Function: • Increases surface area of nasal cavity • Warms, filters, humidifies inhaled air

Question 10

Nasal Cavity

Answer 10

• Located between hard palate and base of skull Description: • Paired cavities separated by nasal septum lined with mucous membrane • Has anterior openings (nares) and posterior openings (choanae) • Conchae on lateral wall Function: • Warm, filter, and humidify inhaled air • Olfaction (smell) Comment: • Part of upper respiratory tract • Mucosa has respiratory and olfactory parts

Question 11

Nasal Septum

Answer 11

• Midline of nasal cavity Description: • Midline structure formed by perpendicular plate of ethmoid, vomer, and nasal septal cartilage • Covered on each side by mucosa Comment: • Commonly deviated from midline, impacting airflow

Question 12

Inferior nasal concha

Answer 12

• Lateral wall of nasal cavity Description: • Shelf-like projection of ethmoid bone covered by thick mucosa Function: • Increases surface area of nasal cavity • Warms, filters, humidifies inhaled air Comment: • Superior and middle nasal conchae are part of ethmoid bone while inferior nasal concha is a separate bone

Question 13

Vomer

Answer 13

• Midline of nasal cavity Description: • Plow-shaped bone Comment: • Forms posterior and inferior part of nasal septum • Articulates with septal cartilage and perpendicular plate of ethmoid bone

Question 14

Inferior nasal meatus

Answer 14

• Located inferior and lateral to inferior nasal concha Description: • Narrow space that contains opening of nasolacrimal duct Function: • Nasal mucosa that lines meatus warms, filters, and humidifies inhaled air

Question 15

Hard Palate

Answer 15

• Located between oral and nasal cavities Description: • Horizontal, bony plate formed by palatine and maxillary bones • Covered by thick mucosa

Question 16

Buccal Fat Pad

Answer 16

Description: • Globular, encapsulated fat body • Prominent in infants Function: • Prevents collapse of cheeks during suckling

Question 17

Oral Cavity

Answer 17

Description: • Two parts: oral vestibule and oral cavity proper • Oral vestibule is space between lips and cheeks (superficial) and teeth and gingivae (deep) • Oral cavity proper is space between maxillary (upper) and mandibular (lower) dental arches • Floor is tongue; roof is hard palate Function: • Functions in mechanical digestion (mastication, i.e., chewing), chemical digestion (initial stage of polysaccharide digestion), taste (via the tongue), ventilation (breathing), and phonation (speaking) Also known as: • Buccal cavity or mouth

Question 18

Buccinator

Answer 18

• Compression of cheek (e.g., inflating a balloon; playing a wind musical instrument) • innervated by Facial nerve (CN VII)

Question 19

Tongue

Answer 19

Description: • Muscular organ with thick mucous membrane containing taste buds • Intrinsic muscles alter shape; extrinsic muscles move tongue • Dense concentration of papillae gives dorsal surface “felt-like” appearance • Divided by V-shaped sulcus terminalis into anterior (oral) part and posterior (pharyngeal) part • Anterior part has median furrow, posterior part is nodular due to presence of lingual tonsils • Lingual frenulum connects tongue to floor of mouth Function: • Mastication (chewing), deglutition (swallowing), and phonation (production of speech sounds) Comment: • Extrinsic muscles: genioglossus, hyoglossus, palatoglossus, and styloglossus

Question 20

Orbit

Answer 20

Description: • Pyramidal space with roof, floor, and medial and lateral walls • Openings include superior and inferior orbital fissures, and optic canal Also known as: • Eye socket Comment: • Contains eyeball and its muscles; cranial nerves II, III, IV, V1, and VI; vasculature; lacrimal apparatus; and fat

Question 21

Optic Nerve (CNII)

Answer 21

Special sensation: • Vision CNS connection: • Lateral geniculate nucleus of thalamus Cranial foramina: • Optic canal • Optic nerve formed by axons of retinal ganglion cells

Question 22

Extrinsic Eye Muscles

Answer 22

• Six voluntary muscles that move eye • Four rectus muscles: superior, inferior, medial, and lateral • Two oblique muscles: superior and inferior

Question 23

Lacrimal Gland

Answer 23

• Lobular gland that secretes watery lacrimal fluid (“tears”)

Question 24

Ethmoidal Cells

Answer 24

Description: • Paired, thin-walled, mucous membrane-lined cavities • Clustered into anterior, middle, and posterior cells • One of paranasal air sinuses Also known as: • Ethmoidal air cells Comment: • Posterior ethmoidal cells open into superior nasal meatus • Anterior and middle ethmoidal cells open into middle nasal meatus • Paranasal sinuses include: frontal, maxillary, and sphenoidal sinuses, and ethmoidal cells (sinus)

Question 25

Olfactory Bulb

Answer 25

• Lies on cribriform plate of ethmoid bone in anterior cranial fossa; ventral aspect of frontal lobe of brain • Site of synapse for olfactory neurons (CN I) after their axons pass through cribriform plate

Question 26

Crista Gali

Answer 26

• Triangular process that projects superiorly from cribriform plate of ethmoid bone Comment: • Contributes to anterior midline portion of anterior cranial fossa • Anterior point of attachment for falx cerebri

Question 27

Falx Cerebri

Answer 27

• Longitudinal fissure between cerebral hemispheres Description: • Large, crescent-shaped fold of meningeal layer of dura mater • Superior margin attached at midline to internal surface of skull Comment: • Superior sagittal sinus located in superior margin • Inferior sagittal sinus located in inferior margin

Question 28

Cribiform Plate

Answer 28

Located on ethmoid bone Description: • Bony plate with foramina (holes) that transmit olfactory nerves (CN I) Comment: • Contributes to anterior midline portion of anterior cranial fossa

Question 29

Sphenoidal Sinuses

Answer 29

Description: • Paired, mucous membrane-lined cavity located on sphenoid bone Comment: • Drains into spheno-ethmoidal recess of nasal cavity • Paranasal sinuses include: frontal, maxillary, and sphenoidal sinuses, and ethmoidal cells (sinus)

Question 30

Olfactory Tract

Answer 30

• Located on ventral aspect of frontal lobe between olfactory bulb and medial aspect of temporal lobe Description: • Bundles of afferent and efferent axons

Question 31

Olfactory Mucosa

Answer 31

Location: • Nasal cavity (superior nasal septum and superior nasal concha and roof between) Description: • Contains olfactory neurons Comment: • Primary function: olfaction

Question 32

Respiratory Nasal Mucosa

Answer 32

Location: • Nasal cavity (inferior two-thirds) Description: • Non-olfactory region of nasal mucosa • Primary function: warm and humidify inhaled air

Question 33

Olfactory Nerve (CNI)

Answer 33

Location • Mucosa of anterosuperior nasal cavity (olfactory epithelium) • Anterior cranial fossa Special sensation: • Olfaction (smell) Cranial foramina: • Cribriform plate of ethmoid bone Comment: • Olfactory nerve formed by proximal process (axons) of olfactory neurons • Olfactory axons project through cribriform plate to synapse in olfactory bulb

Question 34

Septal Nasal Cartilage

Answer 34

Description: • Composed of hyaline cartilage • Posterior aspect joins vomer and ethmoid bone (perpendicular plate)