Facial Bones Flashcards
Identify all of the facial bones? Which are single and which are paired?
2 maxillae 2 zygomatic 2 lacrimal 2 nasal 2 inferior nasal conchae 2 palantine 1 vomer 1 mandible =14 total
What facial bone makes up the prominence of the cheek?
zygomatic or malar bones
What is the largest immovable facial bone?
the 2 maxillary bones
What 7 bones make up the orbit?
Frontal, sphenoid, ethmoid, maxilla, zygomatic, lacrimal and palantine
What projection best demonstrates the orbits?
Modified parietoacanthial waters
What projection best demonstrates the optic foramina? Where should the optic foramina be demonstrated on the radiograph?
Parietoorbital Rheese method, the optic foramen is in the LOQ of orbit
Describe the blow-out fracture?
Occurs when front or base of the orbit is struck solidly, orbital floor fractures and orbital contents blow out the orbital floor
Describe the tripod fracture?
Results from a direct blow to the cheek. Fx at 3 points of attachment of the zygomatic bone: maxilla, temporal and frontal. Results in a free floating zygomatic bone.
Where are the petrous ridges located in the following:
PA Caldwell
Waters
Modified Water
- lower 1/3 of orbits
- just below maxillary sinuses
- lower 1/3 of maxillary sinuses
What bones form the bony nasal septum?
Superiorly- perpendicular plate
Inferiorly-vomer
Anteriorly-septal cartilage
Which facial bones are the most fragile?
Nasal and lacrimal bones
What is cleft palate?
A common congenital defect when there is an incomplete joining of the two palatine processes of the maxilla at birth
What projection can be done if both zygomas are not demonstrated on the SMV?
the tangential oblique axial zygoma SMV
What is the function of the facial bones?
To contribute to the shape and form of a persons face
Is AP or PA preferred for headwork? Why?
PA is preferred for head work because when done AP the lens of the eye received 95% more radiation than when done PA
What passes through the optic foramen?
The optic nerve
What makes up the temporomandibular joint?
the mandibular condyle fitting into the temporomandibular fossa of the temporal bone
What are the basic projections done to demonstrate the mandible? What are the additional ones?
basic: bilateral axial obliques
PA mandible
AP axial Low Down Towne
additional: SMV and panorex
What are the basic projections for demonstrating the TMJ’s? Additional?
basic: AP axial modified towne
Additional: axiolateral obis modified law method
axiolateral schuller method
panorex
tomography
How are TMJs taken radiographically?
bilaterally open and closed mouth
Where is the mandibular condyle when the mouth is open? Closed?
open-condyle moves forward to the front edge of the fossa
closed-condyle lies within the temporomandibular fossa
For the axiolateral oblique projections of the mandible what should be done to best visualize the mentum? Ramus? Body? General survey?
metum-turn head 45 degrees towards IR
Ramus-head in true lateral position
body-head turned 30 degrees towards IR
general survey-head turned 10-15 degrees towards the IR
Explain the differences in the AP towne for skull, mandible and TMJ:
- skull-angle CR 30 degrees caudal to 2.5” above glabella w/ OML and MSP perp
- Mandible- angle CR 35-40 degrees caudal to the glabella w/ OML and MSP perp
- TMJ- angle CR 35 degrees caudal at the level of the TMJ and 2” anterior to EAM w/ OML and MSP perp.
Describe how the orbits project into the skull?
- cone shaped bony walled structure
- they project both upward and toward the midline.
- when OML is parallel to the floor the orbit projects 30 degrees superiorly and towards the MSP at a 37 degree angle.
Describe the inner and outer portions of the orbit:
- the outer circular portion is called the base
- the inner most posterior portion is the apex, and this is where the optic foramen is located.
What is a deviated nasal septum?
occurs when the nasal septum is deflected or laterally displaced from the midline of the nose at the junction of the septal cartilage and the vomer
What does the maxillae articulate with?
2 cranial, 7 facial
- frontal and ethmoid
- zygomatic, lacrimal, nasal, palantine, inferior nasal conchae, vomer, and opposite maxilla.
What does the zygomatic bones articulate with?
3 cranial, 1 facial
- frontal, sphenoid and temporal
- a maxilla
What does the lacrimal bones articulate with?
2 cranial, 2 facial
- frontal and ethmoid
- maxilla and inferior nasal conchae
What does the nasal bones articulate with?
2 cranial 2 facial
- frontal and ethmoid
- maxilla and opposite nasal bone
What does the inferior nasal conchae bones articulate with?
1 cranial, 3 facial
- ethmoid
- maxilla, lacrimal and palantine
What does the palantine bones articulate with?
2 cranial 4 facial
- sphenoid and ethmoid
- maxilla, inferior nasal conchae, vomer, and opposite palantine
What does the vomer articulate with?
2 cranial 4 facial
- sphenoid and ethmoid
- both palantines and both maxilla