Facial Bones and Orbits
Modified Waters Orbits: Eval
Eval: PR displaced by part adjustment rather than CR angulation, EI entire orbit, no rotation, collimation, orbits symmetric
Lateral Facial Bones: Eval
Eval: all facial bones with entire zygomatic bone in center, collimation/marker. almost perfect SI of mandibular rami, SI orbital roof, no rotation of sella turcica
What are the different processes of the maxillary bone?
Frontal process (Superior): Connects with frontal bone below nasal and lacrimal Zygometic processes (lateral): Connects with zygomatic bone Alveolar process (inferior): thick, spongy, horse shoe shaped where teeth are connected Palatine process: connect with palatine bone; forms anterior 3/4 roof of mouth (projects horizontal and medial) Central Portion: Body containing maxillary sinuses Forward projecting process - anterior nasal spine @ acanthion (midpoint) made of maxillary and vomer
Describe the palatine bone. What does it articulate with?
L shaped bone. Horizontal portion articulates with palatine process of maxilla (back 1/4 roof of mouth), Vertical portion is between maxilla and pterygoid process of sphenoid, posterior nasal cavity (forms posterior, medial portions of orbits)
What are the smallest bones in the face?
Lacrimal Bones
Describe the maxillary bone. What does it articulate with?
Largest immovable bone of face. Anchors bone for all other facial bones minus mandible. Forms part of lateral walls/floor of nasal cavity, part of floor or orbits, part of roof of mouth
What are the views that are used to find a foreign body in the orbits?
Lateral and Modified Waters (PA Axial)
Describe TMJ.
Located anterior to EAM. TM fossa isn't deep but allows for large ROM. Mouth is open wide, condyle moved forward to front edge of fossa.
What is the densest bone of the face?
Mandible
What forms the acanthion?
Maxillary and Vomer
Waters Facial Bones: Eval
Orbits, maxilla, zygoma and petrous ridges below the maxillary sinuses, distance between lat border of skull/orbit is equal on both sides, P.R. projected immediately below maxillary sinus
What views are lacrimal bones best seen in?
PA and Lat projection of skull
What is a cleft palate?
Palatine processes do not fuse together
Lateral Orbits: Position, Planes, CR
Position: Affected eye closest to IR, tell pt to look forward Planes: MSP parallel, IPL Perp CR: Perp through outer canthus
Modified Waters Orbits: Position, Planes, CR
Position: Center IR to mid orbit, rest chin on IR Planes: MSP perp, OML makes 50 degree angle with plane of IR CR: perp through mid orbits
Parietoacanthial Projection (Waters) Facial Bones: Positioning, Planes, CR
Position: Hyperextend neck. prone/upright, light 1" beyond shadow of lat sides of face, superiorly to include supraorbital margins - chin (8x10) Planes: OML forms 37 degree angle with plane of IR, MML ~ Perp, MSP perp CR: Perp to exit acanthion
Modified Waters Facial Bones: Positioning, Planes, CR
Position: Less neck extension Planes: OML makes 55 degree angle with IR CR: Exits acanthion
Lateral Facial Bones: Positioning, Planes, CR
Position: Semi prone/upright, Side of injury closest to IR, light field open in front of nose to EAM 10in., Eyebrows to under chin 6in. (Light field should be wider than it is tall... 6x10) Planes: MSP parallel with IR, IPL perp, IOML parallel with transverse axis of IR CR: perp entering lateral surface of zygomatic bone, halfway between the outer canthus and EAM
PA Axial Caldwell Facial Bones: Position, Planes, CR
Position: flexion of neck, upright or supine. Planes: OML perp, MSP perp CR: 15 degrees caudal to exit nasion
Waters Orbits: Position, Planes, CR
Position: hyperextend neck Planes: OML is 37 degrees with plane of IR, MML~ perp, MSP perp CR: perp through mid orbit
PA Axial Orbits: Position, Planes, CR
Position: rest nose and forehead on IR center IR 3/4 distal to nasion. tell pt to hold eyes still Planes: MSP and OML perp CR: 30 Degrees caudal directed through center of orbits.
Describe the zygoma. What does it articulate with?
Prominence of cheek that extends posteriorly. Forms part of lateral wall/floor of orbits (lat aspect of orbits). Connect with frontal bone superiorly. Temporal process is where if connects with temporal bone @ zygomatic process creating an arch. Articulates with zygomatic process of maxilla, articulates with sphenoid bone posteriorly.
What is the function of the facial bones?
Provide structure, shape and support for the face
Modified Waters Facial Bones: SS, Eval
SS: demonstrate blowout fx of orbital floor perp to IR and parallel to CR showing inferior displacement of orbital floor. Eval: Less angulation than waters, PR projected immediately below inferior border of orbits at level midway through maxillary sinus, shows inferior displacement of orbital floor perp to IR and opacified max sinus associated with blow out fx.
PA Axial Caldwell Facial Bones: SS, Eval
SS: maxilla, orbital rims, nasal septum, zygomatic bones, and anterior nasal spine Eval: equal distance from lateral border of skull to lateral border of orbits, PR in bottom 1/3 of orbits and symmetric
What is the hyoid bone?
Small u shaped, located at base of tongue between mandible and trachea. Attached to styloid process of temporal bone by stylohyoid ligaments Two horns: greater cornea (posterior), lesser cornea (anterior
Describe the lacrimal bone. What do they articulate with?
Smallest i face, the fossa on anterior surface holds lacrimal sacs (tear ducts). Lateral to maxillae, forms anterior part of medial wall of orbits
Describe the nasal bone. What do they articulate with?
Superior bone of nasal cavity (the bridge of the nose); small/thin and articulates with frontal bone superiorly, perpendicular plate of ethmoid posteriorly, maxillae laterally, each other medially
What does the mandible articulate with?
Temporal bone: Located under zygoma and doesn't articulate with another bone. - mandibular notch: concave area between two processes - Alveolar portion: supports roots of bottom teeth Mental foramen: passage way for blood vessels/nerves
Describe the vomer bone. What does it articulate with?
Thin plate in MSP of head. Forms interior part of septum. Articulates with perp plate of ethmoid superiorly, sphenoid bone superiorly/posteriorly, maxilla and palatine inferiorly
Describe Inferior Nasal Conchae. What does it articulate with?
Thin, curved, scroll like appearance that extends medially into nasal cavity from the lower third of the lateral wall which is formed by maxilla. The superior and medial portions formed by lateral masses of ethmoid, three nasal conchae project into and divide nasal cavity into superior, middle and inferior meatuses
Per the ARRT, what projections are considered nasal bone projections?
Waters, 2 lats, PA Caldwell
Lateral Facial Bones: Trauma
cross table lateral useful for checking air fluid level in sphenoid sinuses indicating fracture
PA Axial Orbits: Eval
entire orbit, no rotation, PR below orbital margin, bony detail of orbits and soft tissue of eye for localization of foreign bodies, collimation, symmetric visualization or orbits indicating no rotation
What is the purpose of the hyoid bone?
to support the larynx and to serve as the attachment site for muscles of the larynx, pharynx, and tongue
How many bones are in the facial bones group?
14: Nasal (2), Lacrimal (2), Maxillary (2), Zygomatic (2), Palatine (2), Inferior Nasal Conchae (2), Vomer (1), Mandible (1)
How many bones make up the orbits? Name them.
7 bones: Frontal, ethmoid, sphenoid, lacrimal, palatine, maxillary, zygoma
How do you change your CR when evaluating the orbital rims/floor during a PA Axial Caldwell projection?
Change CR from 15 degrees caudal to 30 degrees caudal
Describe the orbits.
Cone shaped with average angle of 37 degrees from MSP. Average angle of 30 degrees superior to OML
What are the two processes of the rami?
Coronoid Process: anterior process that is thin and tapered at higher level than the condylar process Condylar process: posterior process that connects with mandibular fossa of temporal bone to form TMJ.
Lateral Orbits: Eval
Density/contrast permitting optimal visibility of eye/orbit for foreign body, SI orbital roofs, collimation
Describe the mandible bone.
The main body of the facial bones. Contains the mental protuberances (tip where jaw fuses together during 1st year of life), vertical portions (rami) that unite with body are maxibular angle that project superiorly @110-120 degrees.
