Nasal Cavity and Paranasal Sinuses Flashcards
What is the nose? (2)
- Part of the respiratory tract superior to the hard palate and contains the peripheral organ of small
- Includes the external nose and nasal cavity divided by the nasal septum
What are the functions of the nose? (5)
o Olfaction (smelling)
o Respiration
o Filtration of dust
o Humidification of inspired air
o Reception and elimination of secretions from the paranasal sinuses and nasolacrimal ducts
External Nose:
* Dorsum of the nose:
o Extends from the root to the apex
External Nose:
* Nares: (2)
o 2 piriform openings piercing the inferior surface of the nose
o Bond laterally by the alae
External Nose:
* Vestibule: (2)
o Entrance of the nose with various vibrissae (stiff nasal hairs)
o Vibrissae filter dust particles from air entering the nasal cavity since they are usually moist
Skeleton of the External Nose
* Bony part: (3)
o Nasal bones
o Frontal processes of maxillae
o Nasal part of frontal bone
Skeleton of the External Nose
* Cartilaginous part: (3)
o 2 lateral cartilages
o 2 alar cartilages
- U-shaped and move freely
- Dilate or constrict the nares when the muscles
acting on the nose contract
o 1 septal cartilage
What is the Nasal Septum?
Divides the chamber of the nose into 2 nasal cavities.
Bones forming nasal septum: (3)
- Perpendicular plate of ethmoid
- Vomer
- Nasal crests of maxillary and palatine bones
Bones forming nasal septum:
* Perpendicular plate of ethmoid: (2)
o Forms the superior part of the septum
o Descends form the cribriform plate and is
continuous superiorly with the crista galli
Bones forming nasal septum:
* Vomer:
o Forms the posteroinferior part of the
septum
Bones forming nasal septum:
* Nasal crests of maxillary and palatine bones:
o Little contribution
What is the cartilage forming the nasal septum?
- Septal cartilage
o Has tongue-and-groove articulation with
the edges of the bony septum
What are the Nasal Cavities? (2)
- Entered anteriorly through the nares
- Opens posteriorly into the nasopharynx through the choanae
What are the nasal cavities lined with? (2)
- Lined by mucosa except for the nasal vestibule which is lined with skin
- Mucosa is firmly bound to the periosteum and perichondrium
o Continuous with the lining of the nasopharynx, paranasal sinuses, lacrimal sac and conjunctiva
Nasal cavities
* Inferior 2/3 is the ______ area and superior 1/3 is the ______ area
* Air is warmed and moistened in the respiratory area before passing to the lungs
respiratory
olfactory
Boundaries of Nasal Cavities
* Roof: (4)
o Frontal bone
o Nasal bones
o Ethmoid bone (cribriform plate)
o Body of sphenoid
Boundaries of Nasal Cavities
* Floor: (2)
o Palatine process of maxilla
o Horizontal plate of palatine
Boundaries of Nasal Cavities
* Medial wall:
o Nasal septum
Boundaries of Nasal Cavities
* Lateral wall:
o Superior and middle nasal conchae of the ethmoid bone
o Inferior nasal concha
Features of Nasal Cavities
* Nasal conchae:
o Curve __________
o Scroll-like structures and highly convoluted
o Offer vast surface area for heat exchange
o Nasal meatus- underlies each of the bony formations
o Inferior concha is the ______ and _______
o Covered by a mucous membrane that contains large vascular spaces that can enlarge affecting the ______ of the nasal cavity
o When infected or irritated- mucosa covering the _______ may well rapidly blocking the nasal
passages
inferomedially
longest
broadest
caliber
conchae
- The cavity is divided into 5 passages: (5)
o Spheno-ethmoidal recess
o Superior nasal meatus
o Middle nasal meatus
o Inferior nasal meatus
o Common nasal meatus
o Spheno-ethmoidal recess: (2)
- Posterosuperior to the superior nasal concha
- Receives the opening of the sphenoidal sinus
o Superior nasal meatus: (2)
- Narrow passage between the superior and the middle nasal conchae
- Posterior ethmoidal sinuses open here
o Middle nasal meatus: (2)
- Longer and deeper than the superior nasal meatus
- Anterosuperior part opens into the ethmoidal infundibulum through which it communicates
with the frontal sinus
Middle nasal meatus:
Frontonasal duct-
Frontonasal duct- passage leading inferiorly from the frontal sinus to the infundibulum
Middle nasal meatus:
Semilunar hiatus-
Semilunar hiatus- groove into which the frontal sinus opens
Middle nasal meatus:
Ethmoidal bulla-
Ethmoidal bulla- rounded elevation located superior to the semilunar hiatus
Ethmoidal bulla:
* Visible when the _____ _______ is removed
* Formed by the middle ethmoidal cells that form the ethmoidal _________.
middle concha
sinuses
Inferior nasal meatus: (2)
- Horizontal passage inferolateral to the inferior nasal concha
- Nasolacrimal duct opens into the anterior part
Common nasal meatus:
- All 4 lateral passages open here
Vasculature and Innervation of the Nose
Blood supply: (5)
- Anterior ethmoidal a. (from ophthalmic a.)
- Posterior ethmoidal a. (from ophthalmic a.)
- Sphenopalatine a. (from maxillary a.)
- Greater palatine a. (from maxillary a.)
- Septal branch of superior labial a. (from facial a.)
Vasculature and Innervation of the Nose
* First 3 arteries divide into ______ and ______ branches
- First 3 arteries divide into lateral and septal branches
- Greater palatine a. reaches the septum via the _____ _____.
incisive canal
What is the Kiesselbach area?
Kiesselbach area- anterior part of the nasal septum that is the site of an anastomotic arterial plexus involving all 5 arteries.
What is the external nose supplied by?
- External nose supplied by anterior ethmoidal a. and superior labial a.
o Also supplied by infraorbital a. and lateral nasal br. of facial a.
Venous Drainage:
* Submucosal venous plexus: (2)
o Deep to nasal mucosa
o Drains the nose via
- Sphenopalatine v.
- Facial v.
- Ophthalmic v.
Venous Drainage:
* Plays a role in __________
o Exhanges heat and warms air before entering the lungs
thermoregulation
How is the external nose drained?
- External nose drained by facial v. via angular and lateral nasal vv.
Innervation:
* Posteroinferior portion: (2)
maxillary nerve
o Nasopalatine n. – to septum
o Posterior superior and inferior lateral nasal nn. of greater palatine n. – to lateral wall
Innervation:
* Anterosuperior portion:
ophthalmic nerve
o Anterior and posterior ethmoidal nn. of nasociliary n.
Innervation:
* External nose: (2)
o From ophthalmic n. – Infratrochlear n. and external nasal br. of anterior ethmoidal n.
o From maxillary n. – Nasal br of infraorbital n. (to alae)
Innervation:
* Special sensory:
o Olfactory nn.
Paranasal Sinuses: (2)
- Air-filled extensions of the respiratory part of the nasal cavity
- Decrease the weight of the anterior skull and increase vocal resonance
How are paranasal sinuses named?
- Named according to the bones in which they are located
- Sinuses continue to invade the surrounding bone and extensions are common in _____ people
old
What are the frontal sinuses? (2)
- Right and left frontal sinuses are between inner and outer tables of the frontal bone
- Posterior to the superciliary arches and the root of the nose
Frontal sinuses:
How are they drained?
- Drain through the frontonasal duct into the ethmoidal infundibulum which opens into the semilunar hiatus of the middle nasal meatus
Frontal sinuses:
How are they innervated?
- Innervated by branches of the supra-orbital nn. of the ophthalmic n.
What are the Ethmoidal cells/Ethmoidal sinuses?
- Small invaginations of the mucous membrane of the middle and superior nasal meatus into the ethmoid bone between the nasal cavity and the orbit
Ethmoidal cells/Ethmoidal sinuses:
* Anterior ethmoidal cells drain into the middle nasal meatus through the ethmoidal ________
* Middle ethmoidal cells (ethmoidal bulla) open directly into the middle _______
* _______ ethmoidal cells open directly into the superior meatus
infundibulum
meatus
Posterior
Ethmoidal cells/Ethmoidal sinuses:
How are they innervated?
- Innervated by anterior and posterior ethmoidal br. of nasociliary nn. from ophthalmic n.
What are the Sphenoidal sinuses? (2)
- Located in the body of the sphenoid (may extend into the wings)
- Derived from the posterior ethmoidal cells that invade the sphenoid
Sphenoidal sinuses:
* Opens into the ______-______ recess
spheno-ethmoidal
Sphenoidal sinuses:
How are they innervated?
- Supplied by the posterior ethmoidal arteries and nerves
What are the maxillary sinuses? (2)
- Largest of the paranasal sinuses
- Occupy the body of the maxillae and communicate with the middle nasal meatus
Maxillary sinuses:
o Apex-
o Base-
o Roof-
o Floor-
o Apex- extends toward zygomatic bone
o Base- inferior part of the lateral wall of the nasal cavity
o Roof- floor of the orbit
o Floor- alveolar part of the maxilla
Maxillary sinuses:
How are they drained?
- Drains into openings called ostia (singular- ostium) into the middle nasal meatus through the semilunar hiatus
Maxillary sinuses:
* Arterial supply:
o superior alveolar branches of maxillary a.
o descending and greater palatine aa. supply the floor
Maxillary sinuses:
Innervation:
- innervated by anterior, middle and posterior superior alveolar nn. of the maxillary n.
