Download Nasal Cavity - Dr. Meredith

Nasal Cavity and Paranasal Sinuses
Alex Meredith, PhD
I.
Boundaries:
A. Roof: cribriform plate of ethemoid bone; body of sphenoid bone
B. Floor: superior aspect of hard palate, contributions from maxillary
and palatine bones
C. Medial wall: nasal septum found on midline
D. Lateral wall: nasal, maxilla ethmoid and its conchae, palatine,
lacrimal, and inferior nasal concha
II.
Medial Nasal Wall (Septum):
A. Bones:
1. Perpendicular plate of the ethmoid bone, the vomer,
crest of body of sphenoid bone, the palatine crest of
hard palate, septal cartilages and portions of other
cartilages.
B. Blood supply:
1. Posterior ethmoid a.
2. Anterior ethmoid a.
3. Medial posterior nasal (from sphenopalatine a.)
4. Nasopalatine a. (also from sphenopalatine a.,
anastomoses with branches of Greater palatine thru
incisive canal)
5. Septal branch of superior labial a. (from facial a.)
NOTE: Etmoid branches are derived from Ophthalmic a.,
Nasopalatine and Septal from Maxillary a.; therefore,
venous drainage is via Ophthalmic vv. And Pterygoid
plexus.
C. Nerves:
1. Medial nasal branch of Anterior ethmoid n. (from
V1)
2. Nasopalatine n. and Medial (septal) posterior nasal
n. (from sphenopalatine n.) (from V2) CN I
(Olfactory) superiorly
III.
Lateral Nasal Wall:
A. Bones:
1. Nasal
2. Ethmoid
3. Maxilla
4. Frontal
5. Palatine: contains palatine canal with decending
palatine a., greater and lesser palatine n. that give
off posterior inferior later nasal branches directly
thru lateral nasal wall; also the sphenopalatine
foramen that transmits the sphenopalatine n. & a.
with posterior superior lateral nasal branches to the
lateral nasal wall.
6. Lacrimal
7. Inferior concha
B. Nasal Conchae (Turbinates): These are projections of the lateral
nasal wall into the nasal cavity. They have a bony core and are
covered by a highly vascularized mucosa that aids in warming and
moistening inspired air.
1. Superior concha: ethmoid bone
2. Middle concha: ethmoid bone
3. Inferior concha: a separate bone of its own
C. Meati are spaces located inferior and lateral to each concha.
1. Sphenoethmoidal recess: above superior concha
2. Superior meatus: below superior concha
3. Middle meatus: below middle concha
4. Inferior meatus: below inferior concha
D. Ostia or opening in the lateral nasal wall:
1. Sphenoethmoidal recess: opening of the sphenoid
sinus
2. Posterior ethmoid sinuses: open into superior
meatus
3. Openings in middle meatus:
a. Middle ethmoid sinuses on
ethmoidal bulla
b. Hiatus semilunaris
i.
Anterior ethmoid
sinuses
ii.
Frontal sinus via
through the
frontonasal duct to
anterior portion of
hiatus Maxillary sinus
though the posterior
portion of the hiatus
4. Sphenopalatine foramen: transmits sphenopalatine
n. & a.
E. Blood Supply
1. Posterior ethmoid artery (from Ophthalmic a.)
2. Anterior ethmoid artery (from Opthalmic a.)
3. Superior lateral posterior nasal (from
sphenopalatine-from Maxillary a.)
4. Inferior lateral posterior nasal (from decending
palatine-from Maxillary a.)
F. Nerves
1. Anterior ethmoid and its lateral nasal branch (from
V1)
2. Superior lateral posterior nasal (from
sphenopalatine) ( from V2)
3. Inferior posterior nasal (from greater palatine) (
from V2)
4. CN I (Olfactory) superiorly
IV.
Paranasal Sinuses
A. Maxillary sinus: within the maxilla and communicates with the
nasal cavity though an opening in the posterior portion of the
hiatus semilunaris in the middle meatus. The roots of the maxillary
teeth project into wall of this sinus and nerves to these teeth are
within the wall mucosa as well. Thus, sinusitis may result in the
perception of tooth pain.
B. Ethmoid sinuses: numerous air pockest within the body of the
ethmoid bone. Although divided into anterior, middle and posterior
groups all actually interconnect. Posterior ethmoid sinuses drain
into the super meatus of the nasal cavity; middle ethmoid sinuses
connect to the nasal cavity through small opening on the ethmoidal
bulla, and anterior ethmoid sinuses drain directly into the hiatus
semilunaris.
C. Frontal sinus: within the frontal bone superior to each orbit.
Connect via the frontonasal duct to the anterior aspect of the hiatus
semilunaris in the middle meatus.
D. Sphenoid sinus: within the sphenoid bone inferior to the sella
turcica, often exhibit a thin, midline septum separating right and
left pahenoid sinuses.