frontal bones/ paranasal sinuses Flashcards
paranasal sinuses
4 groups of air containing cavities
lined with mucous membrane
communicate with nasal cavity
paranasal sinuses in the skull
ethmoid bone (many) sphenoid bone (1 or 2) frontal bone (2)
paranasal sinuses in the facial bones
maxillary bone (2)
believed to be functions of paransal sinuses
resonating chamber for voice decrease weight of skull warm and moisten inhaled air shock absorbers in trauma possibly control immune system
paranasal sinuses begin to develop in
the fetus
only what sinuses are demonstrated radiographically at birth?
maxillary sinuses
frontal and sphenoid sinuses are visible radiographically when?
at age 6 or 7
ethmoid sinuses fully develop when
by late teenage years
maxillary sinuses
located in body of each maxillary bone
shaped like a pyramid from front
cube shaped from side
correspond to the roots of the upper molar teeth
T or F
All paranasal sinuses communicate with each other and with the nasal cavity which is divided into two fossae
true
what are 2 older terms for your maxillary sinuses
antrum
antrum of highmore
all radiographic positioning for for sinuses should be done in the
upright position
frontal sinuses
located between the inner and outer tables of skull posterior to glabella
two cavities generally separated by a septum but not always
rarely aerated before age 6
t or f frontal sinuses are generally larger in males
true
ethmoid sinuses
contained within lateral masses of ethmoid
divided into 3 groups
3 groups of ethmoid sinuses
anterior
middle
posterior
sphenoid sinuses
directly below sella turcica
can be paired or a single cavity
air fluid levels can indicate a basal skull fracture
osteomeatal complex
pathways of communication between paranasal sinuses and provide drainage between them
an obstructed osteomeatal complex can lead to
sinusitis or infection
osteomeatal complex can be imaged with
CT
2 key passageways in the osteomeatal complex
- infundibulum
2. middle nasal meatus
the maxillary sinuses drain through the ?
to the?
infundibulum
middle nasal meatus into inferior nasal meatus
frontal and ethmoid sinuses drain into?
ethmoid bulla and then through the middle nasal meatus into inferior nasal meatus
frontal sinuses
visualized between inner and outer table of skull
sphenoid sinuses
appear to be continuous with ethmoid sinuses
facial bones form several cavities which include
oral cavity
nasal cavity
orbits
the long axis of the orbit projects superiorly how many degrees
30 degrees
the long axis of the orbit projects medially how many degrees
37 degrees
clinical indications of facial bones and paranasal sinuses
- fractures
- foreign body of the eye
- neoplasms
- osteomyelitis
- sinusitis
- secondary osteomyelitis
- TMJ syndrome
- fractures
3 types
a. tripod fracture
b. LeForte fractures
C. contrcoup fractures
a. tripod fractures
caused by a blow to the cheek
zygoma will fracture in 3 places
the orbital process, maxillary process, and temporal process
its free floating and unstable
b. LeForte fractures
severe bilateral horizontal fractures of maxilla
may result in unstable detached fragment
c. contrecoup fractures
injury/ fracture to the side of a structure caused by an impact on the opposite side
- foreign body of the eye
metal or other types of fragments in the eye
plain images can detect metallic foreign objects
- neoplasms
new and abnormal growth
- osteomyelitits
localized infection of bone/ bone marrow
- sinusitis
infection of the sinus mucosa
can be acute or chronic
- secondary osteomyelitis
infection of bone and marrow secondary to sinusitis
results in erosion of bony margins of sinus
- TMJ syndrome
describes a set of symptoms which may include pain and clicking that indicate dysfunction of the TMJ
facial bones routine projections
lateral
parietoacanthial (waters method)
PA axial (caldwell method)
facial bones special projections
modified parietoacanthial (modified waters)
nasal bones routine projections
lateral
parietoacanthial (waters)
nasal bones special projections
superoinferior tangential (axial)
zygomatic arches routine projections
submentovertex (SMV) oblique inferosuperior (tangential) AP axial (modified Towne)
zygomatic arches special projections
parietoacanthial (waters)
Lateral
optic foramina routine projections
parietoorbital oblique (Rhese) parietoacanthial (waters)
optic foramina special projections
modified parietoacanthial (modified waters)
mandible routine projections
axiolateral oblique
PA 0 degrees (20-25 degrees cephalad
AP axial (Towne)
mandible special projections
SMV
orthopantomography (panoramic tomography)
TMJ routine projections
AP axial (modified towne)
TMJ special projections
axiolateral 15 degree oblique (modified law)
axiolateral (schuller)
orthopantomography
paranasal sinuses routine projections
lateral
PA caldwell
parietoacanthial (waters)
paranasal sinuses special projections
SMV parietoacanthial transoral (open mouth waters)
overpenetration of sinuses
diminishes or obliterates existing pathologic conditions
easy to miss something
underpenetration of sinuses
can simulate pathologic conditions that do not exist
