Orbits and Facial Bones
What line is parallel to the IR in the SMV of zygomatic arches?
IOML
What line is parallel with he long axis of the cassette for laterals?
IOML
What line is perpendicular to the IR for the modified townes of the facial bones at 37º caudal angle?
IOML
Which line is parallel to the IR doe the tangential projection of the zygomatic arches?
IOML
What shape are the palatine bones?
L shaped
What line is perpendicular to the IR when shooting a modified waters?
MML
What line is perpendicular to the IR when shooting a reverse waters?
MML
What line is perpendicular to the IR when shooting a waters?
MML
What plane is parallel to the IR for laterals?
MSP
What plane is perpendicular to the IR in a modified waters of the orbit?
MSP
Where do the 2 nasal bones articulate with each other?
MSP
What line is perpendicular to the IR for the Caldwell of the facial bones?
OML
What line is perpendicular to the IR for the modified townes of the facial bones at 30º caudal angle?
OML
Which baseline is used to position the parietoacanthial (modified Waters) projection of the eye?
OML
In what projections of the skull can you visualize the lacrimal bones?
PA and lateral
Which special projection of the eye involves the use of the CR angulation to project the petrous ridges out of the orbits?
PA axial
What is the 3 point landing projection?
Rhese
Which projections shows a bilateral view of the zygomatic arches without superimposition?
SMV of the zygomatic arches
What is the only freely movable joint of the face?
TMJ
What is the midpoint of the anterior nasal spine referred to as?
acanthion
Where do you center for a reverse waters?
acanthion
What type of bone is the hyoid in relation to the axial skeleton?
accessory bone
Which bones does the maxilla articulate with?
all facial bones except the mandible
What are the boney features that provide attachments for the teeth called (on the maxilla and mandible)?
alveolar processes
How do you angle the tube for a reverse waters, in a trauma situation, where the patient cannot tilt his had to make his OML 37º from the IR?
angle to be parallel to the MML
In the anterior MSP at the junction of the two maxillary bones, a forward-projecting process is formed. What is it called?
anterior nasal spine
Where are the petrous ridges in a waters?
below apex of maxillary sinus
Where are the petrous ridges in a modified waters?
below orbits, midway through maxillary sinus
Define Le Fort fracture
bilateral, horizontal fractures of the maxilla
What is the curved horizontal portion of the mandible called?
body
What is the superior boney wall of the nasal cavity more commonly known as?
bridge of the nose
What touches the Bucky for the Rhese?
cheek, nose, chin
What touches the Bucky for a waters?
chin, nose 3/4 inch away
What is the TMJ formed by?
condyle of the mandible and the mandibular fossa of the temporal bone
Where is the TMJ located in relation to the EAM?
directly in front
Define TMJ syndrome
dysfunction of the TMJ
Medial back side of orbit...
ethmoid
The upper 2 nasal conchae are processes of what bone?
ethmoid
Where do you center for a modified waters of the facial bones?
exiting the acanthion
Where do you center for a waters of the facial bones?
exiting the acanthion
Where do you center for the PA axial Caldwell of the facial bones?
exiting the nasion
What type of joints are the alveolar sockets?
fibrous, gomphosis, immovable
Define blowout fracture
fracture of the floor of the orbit
Define tripod fracture
fracture of the zygomatic arch and orbital floor or rim, and dislocation of the frontozygomatic suture
Define contre-coup fracture
fracture to one side of the structure caused by trauma to the other side
Roof of the orbit...
frontal
What does the zygoma articulate with superiorly?
frontal
What 2 cranial bones does the maxilla articulate with?
frontal and ethmoid
What do the nasal bones articulate with superiorly?
frontal bone
What 4 bones does the lacrimal bone articulate with?
frontal, ethmoid, maxilla, inferior nasal concha
Three of the bones making up the orbit are cranial bones - what are they?
frontal, sphenoid, ethmoid
List the 7 bones that make up the orbit
frontal, sphenoid, ethmoid, maxilla, zygoma, lacrimal, palatine
What 3 bones make up the outer rim of the orbit?
frontal, zygoma, maxilla
What is another term for the angle of the mandible?
gonion
What is the name of the U shaped bone, situated at the base of the tongue?
hyoid
Define osteopetrosis
increased density of atypical soft bone
What bones extend diagonally and inferiorly from the lateral walls of the nasal cavity, curling laterally giving them a scroll-like appearance?
inferior nasal conchae
Define osteomyelitis
inflammation of the bone due to pyogenic infection
What passes through the infraorbital foramen?
infraorbital nerve and artery
What line is perpendicular to the IR for laterals?
interpupillary line
Anterior part of the medial wall of orbit...
lacrimal
Which facial bone is located at the medial wall of the orbit?
lacrimal
What are the smallest bones of the skull?
lacrimal bones
Where do the tear ducts pass through?
lacrimal foramina
Which projections are used to demonstrate radiopaque foreign objects in the eye?
lateral, PA axial, modified Waters
Why are special projections of the eye done?
localize radiopaque foreign bodies in the eye
Define osteoporosis
loss of bone density
Where are the petrous ridges for the Caldwell of the facial bones?
lower 1/3 of the orbit
What is another name for the zygomatic bone?
malar bone
Where is the mental foramen located?
mandible
What are the two processes of each ramus of the mandible separated by?
mandibular notch
Part of the floor of the orbit...
maxilla
What does the zygoma articulate with anteriorly?
maxilla
What is the largest immovable bone of the face?
maxilla
Where is the infraorbital foramen located?
maxilla
What 4 facial bones make up the orbit?
maxilla, zygoma, lacrimal, palatine
What do the nasal bones articulate with on each lateral side?
maxillae
The mandible fuses within the first year of life. What is the ridge at which it fuses called?
mental protuberance
Where do you center for the modified waters of the orbit?
midorbit
What projections best shows a blowout fracture?
modified waters
What portion of the nasal cavity does the maxilla form?
most of the lateral portion and floor of the nasal cavity
What are the inferior nasal conchae covered with and why?
mucous membrane - to warm, moisten, and cleanse inhaled air
Is the mandible a paired bone?
no
What touches the Bucky for a modified waters?
nose and chin
What structures are shown on a waters facial bones?
orbits, maxilla, zygomatic arches
Where do you center for the lateral orbit?
outer canthus
Posterior part of the medial wall of orbit...
palatine
Which facial bone is located at the inferior apex of the orbit?
palatine
Which facial bone is located at the posterior portion of the roof of the mouth?
palatine
What makes up for the other 1/4 of the roof of the mouth
palatine bones
Which special projection of the eye involves the use of part position to project the petrous ridges out of the orbits?
parietoacanthial projection (modified Waters method)
What portion of the orbit does the maxilla form?
part of the floor of the orbital cavities
What part of the orbit do the palatine bones make up?
part of the posteromedial portion
What part of the orbit does the zygomatic bone make up?
part of the side wall and floor
What are the two vertical portions of the mandible called?
rami
Which facial bone projection demonstrates the superior facial bones with magnification?
reverse waters method
How do you position a tangential projection of the zygomatic arches?
rotate the MSP 15º towards the side of interest, tilt the top of the head 15º away from the side of interest
When shooting PA, which side are we looking for?
side down
Which side are you looking for in a Rhese?
side down
Lateral back side of orbit...
sphenoid
What does the zygoma articulate with posteriorly?
sphenoid
What structures are shown on a reverse waters?
superior facial bones
What are the structures shown on the AP axial modified townes of the zygomatic arches?
symmetric projection of both zygomatic arches, free of superimposition
What type of joint is the TMJ?
synovial, hinge and gliding, freely movable
How does the hyoid relate to the facial bones?
the hyoid is held in place by the stylohyoid ligaments, which extend from the styloid processes of the temporal bones
What forms the zygomatic arch?
the junction of the zygomatic process of the temporal bone and the temporal process of the zygomatic bone
What structures are shown on a Rhese?
the optic foramen lying in the inferior and lateral quadrant of the projected orbit
Where does the maxilla articulate with the zygoma?
the zygomatic process
What bone is situated on the MSP on the floor of the nasal cavity?
vomer
Which facial bone forms the inferior portion of the nasal septum?
vomer
What method is the parietoacanthial projection?
waters, modified waters
Where are the petrous ridges in a modified waters of the orbit?
well below orbital shadows
When is the tangential projection of the zygomatic arch particularly useful?
when a patient has a depressed fracture or flat cheekbones
What is cleft palate?
when the maxilla does not fuse together properly
When is a reverse waters done?
when the patient cannot be placed PA
Are the sphenoid, palatine, and maxilla all parts of the bony labyrinth?
yes
Does the maxilla contain paranasal sinuses?
yes
Does the maxilla feature special bone that holds the roots of the teeth?
yes
Can a Rhese be done AP?
yes, but eye dose will increase
Part of the lateral wall and floor of the orbit...
zygomatic
Which facial bone features a frontal process?
zygomatic
What does the zygoma articulate with laterally?
zygomatic process of temporal bone
Structures shown on the tangential projection of the zygomatic arch?
1 arch, free of superimposition
What two processes do each ramus of the mandible present?
1 coronoid, 1 condylar
Where do you center for a Rhese?
1" above and 1" posterior to the TEA
Where do you center for the SMV of the zygomatic arches?
1" posterior to the outer canthus
Where do you center for the tangential projection of the zygomatic arches?
1" posterior to the outer canthus
2 evaluation criteria for lateral of the facial bones?
1. Superimposed orbital roofs 2. Sella turcica in profile
2 evaluation criteria for the Rhese
1. entire orbital rim 2. supraorbital margins lying in the same horizontal line
2 evaluation criteria for modified waters of the orbit
1. entire orbits 2. petrous ridges well below orbital shadows
2 evaluation criteria for lateral orbit
1. entire orbits 2. superimposed orbital roofs
2 evaluation criteria for the reverse waters of facial bones
1. entire orbits and facial bones 2. petrous ridges projected immediately below maxillary sinuses
2 evaluation criteria for waters of the facial bones
1. entire orbits and facial bones 2. petrous ridges projected immediately below maxillary sinuses
2 evaluation criteria for the Caldwell of the facial bones
1. entire orbits and facial bones 2. petrous ridges projected in the lower 1/3 of orbit
2 evaluation criteria for the modified waters of the facial bones
1. entire orbits and facial bones 2. petrous ridges projected midway through the maxillary sinuses
2 evaluation criteria for the AP axial modified townes of the zygomatic arches
1. no overlap of zygomatic arches by mandible 2. symmetric arches
Evaluation criteria for tangential projection of the zygomatic arch
1. zygomatic arch free from overlying structures
2 evaluation criteria for SMV of zygomatic arches
1. zygomatic arches free from overlying structures 2. zygomatic arches symmetric and without foreshortening
Where do you center for the lateral facial bones?
1/2 distance from OC to EAM
How many facial bones are there?
14
What is the angle of the CR in a PA axial Caldwell of the facial bones?
15º caudal
How many mental foramen do you have?
2, they are bilateral
How much of the roof of the mouth does the maxilla make up?
3/4
What is the central ray orientation for the PA axial special projection of the eye?
30º caudal
What angle is the OML at for a reverse waters?
37º
What angle is the OML at for the waters?
37º
What is the SID for all facial bones?
40"
What angle is the MSP at in a Rhese?
53º
What angle is the OML at for the modified waters?
55º
What angle should the OML be at in a modified waters of the orbit?
55º
How many bones is the orbit composed of?
7
What kVp are most all facial projections shot at?
80 kVp
What is the exaggerated Caldwell and what does it show?
Caldwell with a 30º angulation to show the orbital rims, particularly the orbital floors
