Ch.11 - Cranial Bones, Facial Bones, & Paranasal Sinuses (RAD 122)
What sinuses are demonstrated on an SMV radiograph?
Sphenoid & ethmoid sinuses
Describe the positioning & CR centering for the Lateral projections of the skull.
-10x12 IR crosswise -place head in a true lateral position & align the IPL perpendicular to the IR -center 2" superior to the EAM w/ a perpendicular CR (halfway between glabella & inion for other skull morphologies)
Describe positioning & CR centering for the AP axial (Towne method).
-10x12 IR lengthwise -In an AP position, bring patient's chin down until OML is perpendicular to the IR -Direct CR 2 1/2" above the glabella (@ hairline) w/ a 30 degree caudad CR angle
Describe positioning & CR centering for the SMV skull projection
-10x12 IR lengthwise -place IOML parallel to IR -CR perpendicular to IOML & centered 1 1/2" inferior to mandibular symphysis (midway between the gonions)
Describe positioning & CR centering for the PA 0 degree CR projection of the skull.
-10x12 IR lengthwise -rest patient's nose & forehead against IR & align the OML to be perpendicular to the IR -perpendicular CR centered to exit @ the glabella
Describe positioning & CR centering for the PA axial (Haas Method)
-10x12 IR lengthwise -rest patient's nose & forehead against IR & bring the OML perpendicular to IR -25 degrees cephalic angle to pass through level of EAMs & exit 1 1/2" superior to nasion
Describe positioning & CR centering for the PA axial (Caldwell Method).
-10x12 IR lengthwise -rest patient's nose & forehead against table/bucky, & flex neck until OML is perpendicular to IR -angle CR 15 degrees caudad & center to exit @ the nasion
Describe positioning & CR centering for the Axiolateral Oblique projection of the mandible
-8x10 IR -True lateral (IPL perpendicular to IR) to show ramus -rotate head 30 degrees from true lateral to show body -rotate head 45 degrees from true lateral to show mentum -rotate head 10-15 degrees from true lateral for general survey -CR 25 degrees cephalic to area of interest for all
Describe positioning & CR centering for the Lateral nasal bone projections.
-8x10 IR -place head in a true lateral position by placing the IPL perpendicular to the IR -perpendicular CR directed 1/2" inferior to the nasion (*both lateral should be taken for comparison & close collimation should be used!)
Describe positioning & CR centering for the AP axial (Modified Towne) projection of the TMJs?
-8x10 IR crosswise -if OML is perpendicular to the IR, then a 35 degree caudad CR angle should be used to enter 3" above the nasion -if IOML is perpendicular to the IR, then a 42 degree caudad CR angle should be used to enter 3" above the nasion
Describe positioning & CR centering for the AP axial (Towne) projection of the zygomatic arches
-8x10 IR crosswise -patient in an AP position w/ OML aligned perpendicular to IR -30 degree caudad CR centered to enter 1" superior to the glabella
Describe positioning & CR centering for the SMV zygomatic arch projection
-8x10 IR crosswise -raise patient's chin until IOML is parallel to the IR -align CR perpendicular to IR & direct it 1 1/2" inferior to the mandibular symphysis (*zygomatic arches visualized bilaterally)
Describe positioning & CR centering for the special SMV projection of the mandible
-8x10 IR lengthwise -IOML parallel to IR -CR perpendicular to IR directed 1 1/2" inferior to mandibular symphysis
Describe positioning & CR centering for the Axiolateral (Schuller) projection of the TMJs
-8x10 IR lengthwise -IPL perpendicular to IR -25 degree caudad CR to enter 1/2" anterior & 2" superior to the EAM (*both an open & closed mouth projection should be taken for comparison)
Describe positioning & CR centering for the open mouth Water's projection of the sinuses
-8x10 IR lengthwise -MML perpendicular to IR then instruct the patient to drop their jaw -perpendicular CR to exit @ acanthion
Describe positioning & CR centering for the PA 0 degree CR mandible projection
-8x10 IR lengthwise -OML perpendicular to IR -perpendicular CR to exit @ the junction of the lips (*for a true PA of the body bring AML perpendicular to IR)
Describe positioning & CR centering for the AP axial (Towne) projection of the mandible
-8x10 IR lengthwise -OML perpendicular to IR = 35 degree caudad CR to enter @ the glabella -IOML perpendicular to IR = 42 degree caudad CR to enter @ the glabella
Describe positioning & CR centering for the PA axial (Caldwell Method) for the facial bones.
-8x10 IR lengthwise -Patient in a PA position w/ the OML perpendicular to the IR -15 degree caudad CR to exit @ the nasion (*the only difference in the facial Caldwell from the skull Caldwell is collimation!)
Describe positioning & CR centering for the Modified Water's projection of the facial bones.
-8x10 IR lengthwise -adjust patient's head until the LML is perpendicular to the IR (OML should form a 55 degree angle w/ the IR) -perpendicular CR to exit @ the acanthion
Describe positioning & CR centering for the Oblique Inferosuperior (Tangential) projection of the zygomatic arches
-8x10 IR lengthwise -align IOML parallel to IR, rotate the head 15 degrees toward side of interest & tilt head 15 degrees toward side of interest -perpendicular CR directed to arch of interest (*zygomatic arch of interest visualized unilaterally)
Describe positioning & CR centering for the PA (Caldwell) projection of the sinuses
-8x10 IR lengthwise -align OML to be 15 degrees from horizontal by placing only the tip of the patient's nose against the IR -Perpendicular CR to exit at the nasion
Describe positioning & CR centering for the Axiolateral Oblique (Modified Law) projection of the TMJs
-8x10 IR lengthwise -bring IPL perpendicular to IR, then rotate the head 15 degrees toward the IR -15 degree caudad CR to enter 1 1/2" above the EAM (*an open & closed mouth projection should be taken for comparison)
Describe positioning & CR centering for the Parietoacanthial (Water's) projection of the facial bones.
-8x10 IR lengthwise -extend neck to place chin against IR & align MML to be perpendicular to the IR (OML should form a 37 degree angle to the IR) -perpendicular CR to exit @ the acanthion
Describe positioning & CR centering for the Lateral projection of the sinuses
-8x10 IR lengthwise -head in true lateral position by aligning IPL to be perpendicular to the IR -perpendicular CR centered midway between EAM & outer canthus (zygoma)
Describe positioning & CR centering for the SMV projection of the sinuses
-8x10 IR lengthwise -place IOML parallel to IR -CR perpendicular to IOML centered 1 1/2" inferior to the mandibular symphysis
Describe positioning & CR centering for the Water's projection of the sinuses
-8x10 IR lengthwise -place MML perpendicular to the IR -perpendicular CR to exit @ the acanthion
Describe the positioning & CR centering for a lateral projection of the facial bones.
-8x10 IR lengthwise -place head in a true lateral position by aligning the IPL to be perpendicular to the IR -perpendicular CR directed to the zygoma (midway between the outer canthus & the EAM)
What bones does each inferior nasal concha articulate w/?
1 cranial bone-ethmoid 3 facial bones-maxilla, lacrimal & palatine
What 6 bones does the occipital bone articulate with?
1)2 parietal bones 2)2 temporal bones 3)sphenoid 4)C1 (atlas)
What 4 cranial bones does the frontal bone articulate with?
1)R. Parietal 2)L. Parietal 3)Ethmoid 4)Sphenoid
What 2 main parts make up the frontal bone?
1)Squamous portion - forms the forehead 2)Orbital/horizontal portion - forms superior part of orbits
1)anterior fontanel of an infant forms what in an adult skull? 2)posterior fontanel forms what in an adult? 3)R. & L. Sphenoid fontanels form what in an adult? 4)R. & L. Mastoid fontanels form what in an adult?
1)bregma 2)lambda 3)R. & L. Pterions 4)R. & L. Asterions
What 2 main sets of bones is the skull divided into?
1)cranial bones (8) 2)facial bones (14)
What are the 3 pairs of small openings that exist in the greater wings of the sphenoid for passage of certain cranial nerves?
1)foramen rotundum 2)foramen ovale 3)foramen spinosum
What 5 cranial bones does each parietal bone articulate with?
1)frontal 2)occipital 3)temporal 4)sphenoid 5)opposite parietal
What are the 4 processes of each maxilla?
1)frontal process 2)zygomatic process 3)alveolar process 4)palatine process
Each maxilla assists in the formation of what 3 cavities of the face?
1)mouth 2)nasal cavity 3)one orbit
What are the 3 primary parts of the temporal bone?
1)squamous portion(upper portion that forms part of the wall of the skull) 2)mastoid portion(posterior to the EAM where many air cells are located) 3)petrous portion(anterior portion that houses organs of hearing & equilibrium)
What bones does each nasal bone articulate with?
2 cranial bones-frontal & ethmoid 2 facial bones-maxilla & adjacent nasal bone
What bones does each lacrimal bone articulate with?
2 cranial bones-frontal & ethmoid 2 facial bones-maxilla & inferior nasal concha
What bones does each palatine bone articulate w/?
2 cranial bones-sphenoid & ethmoid 4 facial bones-adjacent palatine, vomer, inferior nasal conchae & maxilla
The ________ are suspended from the undersurface of the cribriform plate on each side of the perpendicular plate.
2 lateral labyrinths (masses)
Projecting downward from the inferior surface of the body of the sphenoid are 4 processes that correspond to the "legs" of the imaginary bat, list these.
2 lateral pterygoid processes & 2 medial pterygoid processes (form part of the lateral walls of the nasal cavities)
What are the largest immovable bones of the face?
2 maxillae
List the facial bones:
2 maxillae, 2 zygoma, 2 lacrimal, 2 nasal, 2 inferior nasal conchae, 2 palatine, vomer, & mandible
The lateral walls of the cranium & part of the roof are formed by the _________.
2 parietal bones
Each orbit is composed of what 7 bones?
3 cranial-frontal, ethmoid, sphenoid 4 facial-lacrimal, maxilla, zygoma, palatine
What SID should be used for all cranium, facial, & paranasal sinuses radiography?
40" SID
Due to the thick & gelatin-like composition of the fluid within the paranasal sinuses, allow at least __ minutes to pass once a patient has been changed from a recumbent to an erect position so that the fluid can settle.
5
What is an acceptable kV range for radiography of the cranium & facial bones?
65-85 kV
What is the average difference between the GML & the OML, as well as between the OML & the IOML?
7-8 degrees
At what age do the 2 mandibular bones join & become one large single bone?
@ approximately 1 year of age
Where are the petrous pyramids projected on the 25-30 degree Modified Caldwell projection?
@ or just below the IOM to allow visualization of entire orbital margins
Better visualization of the orbital margins can be achieved by using the Modified Caldwell Method, which requires what?
A 25-30 degree caudad CR angle to exit @ the nasion
What projection of the skull best demonstrates the sella turcica & the dorsum sellae?
A lateral projection
A)What 4 cranial bones make up the calvarium (skullcap)? B)What 4 cranial bones make up the floor?
A)Frontal bone, R. & L. Parietal bones, & Occipital bone B)R. & L. Temporal bones, Sphenoid bone, & Ethmoid bone
For lateral projections of the skull, A)rotation is evident by what? B)tilt is evident by?
A)anterior-posterior separation of symmetric vertical structures B)superior-inferior separation of symmetric horizontal structures
The area anterior to the angle is known as the A)_______ & the area superior to the angle is termed the B)______.
A)body B)ramus
Each end of the Sagittal suture is identified as a specific point, A)what is the anterior end called? B)what is the posterior end called?
A)bregma B)lambda
The process @ the anterior end of the mandibular notch is the A)______ & the process @ the posterior end is the B)______.
A)coronoid process(doesn't articulate with another bones & serves as a site for muscle attachment) B)condyloid process(its head fits into the TM fossa of the temporal bone for form the TMJ)
What A)cranial bones & B)facial bones does each maxilla articulate w/?
A)frontal & ethmoid B)zygoma, palatine, inferior nasal conchae, vomer, lacrimal, nasal, & adjacent maxilla
What A)cranial bones & B)facial bones does each zygoma articulate w/?
A)frontal, sphenoid, temporal B)maxilla
A)where the eyelids meet near the nose B)lateral junction of the eyelids
A)inner canthus B)outer canthus
A)What 3 cranial bones does each temporal bone articulate with? B)What 2 facial bones does each temporal bone articulate with?
A)sphenoid, parietal, occipital B)zygoma, mandible
Extending anteriorly from the squamous portion of the temporal bone is an arch of bone known as the A)______, which meets the temporal process of the zygomatic bone to form the B)_______.
A)zygomatic process B)zygomatic arch
Connects the acanthion to the EAM
AML - acanthiomeatal line
What is the routine projection for the TMJs?
AP axial (Modified Towne's)
What projections are included in a skull series routine?
AP axial (Towne Method) Lateral PA axial (Caldwell Method) PA 0 degrees
The midline point @ the junction of the upper lip & the nasal septum
Acanthion
When do the frontal & sphenoid sinuses develop?
Age 6 or 7
What should be done if the patient is unable to depress their chin sufficiently enough to bring the OML perpendicular to the IR?
Align IOML perpendicular to IR & increase CR angle to 37 degrees caudad to enter 1" superior to the glabella
What sinuses are demonstrated on the Lateral radiograph?
All 4 paranasal sinus groups
What bones does the sphenoid bone articulate with?
All 7 of the other cranial bones & 5 facial bones (R. & L. Palatine bones, R. & L. Zygomatic bones, & vomer)
True/false: The lower teeth are rooted in the mandible in the superior portion known as what?
Alveolar process
The _____ of the mandible divides each half of the mandible into 2 main parts.
Angle ( gonion)
The 2 maxillae are solidly united in the midline anteriorly, @ the upper portion of the union is the ________.
Anterior nasal spine
What is an older term for the maxillary sinuses?
Antrum
The 2 lateral occipital condyles on each side of the foramen magnum articulate with C1 to form what joint?
Atlanto-occipital joint
Large flap of the ear made of cartilage
Auricle (pinna)
The center point of the EAM is known as what?
Auricular point
What are the special projections for the TMJs?
Axiolateral Oblique (Modified Law) & Axiolateral (Schuller)
What is the positioning routine for the Mandible?
Axiolateral Oblique, PA or PA axial, AP axial (Towne)
Air-fluid levels in the sphenoid sinuses may indicate that the patient has a _______.
Basal skull fracture
The widest portion of the entire skull is located where?
Between the parietal tubercles (eminences) of the 2 parietal bones.
What is the name for a fracture of the floor of the orbit caused by an object striking the eye straight on?
Blowout fracture
What skull morphology falls under the description of the width of the skull being 80% or more of the length of the skull?
Bradycephalic(angle between the petrous pyramids & the MSP is +/- 54 degrees)
A common congenital defect called a _______ is an opening between the palatine processes of the maxillae that is caused by incomplete joining of the 2 bones.
Cleft palate
______ is a shallow depression that begins on the posteroinferior aspect of the Dorsum sellae & extends posteriorly to the foramen magnum @ the base of the occipital bone.
Clivus (forms base of support for the pons & basilar artery)
What is demonstrated on a Modified Law radiograph?
Condyloid process within TM fossa for the closed mouth & condyloid process @ anterior margin of TM fossa for open mouth
What is demonstrated on a PA axial (Modified Towne) radiograph of the TMJs?
Condyloid processes & TM fossae
What suture separates the frontal bone from the 2 parietal bones?
Coronal suture
The small upper horizontal portion of the ethmoid that contains many small openings through which branches of the olfactory nerves pass
Cribriform plate
Projecting superiorly from the cribriform plate is the ______.
Crista galli ("rooster's comb")
Clinical condition wherein the nasal septum is deflected or displaced laterally from the midline of the nose, which can make breathing difficult & in some cases impossible.
Deviated septum
What skull morphology falls under the description of the width being less than 75% of the length of the skull?
Dolichocephalic(angle between the petrous pyramids & the MSP is +/- 40 degrees)
Posterior to the sella turcica is the back of the saddle known as the _______.
Dorsum sellae
What 2 bones form the bony nasal septum?
Ethmoid & vomer
What sinuses are the last to develop?
Ethmoid (late teens)
The lateral masses contain _________ & help to form the medial walls of the orbits & the lateral walls of the nasal cavity.
Ethmoid air cells (sinuses)
_______ lies primarily below the floor of the cranium & only the top is shown on a superior view situated between a notch of the frontal bone.
Ethmoid bone
Each orbital plate is separated from the other by the _______.
Ethmoid notch
Describe positioning & CR centering for the Water's projection of the nasal bones.
Everything is the exact same as it is for facial bones, the only difference is closer collimation for nasal bones
How do you position for the Water's projection of the zygomatic arches?
Exact same as Water's for facial & nasal bones
What is visualized on the Lateral facial bones projection?
Facial bones of the side closest to the IR
True/False: The frontal sinuses are generally larger in women than in men.
False
True/false: Cartilage does not make up the majority of the nose.
False
True/false: The pyramid-shaped petrous portion of the temporal bone is not the thickest & densest bone in the cranium.
False
The articulations or joints of the cranium are called sutures & are classified as _________.
Fibrous, synarthrodial type joints
What is the classification, mobility type, & movement type of the joints between the alveoli & the roots of the teeth?
Fibrous, synarthrodial, gomphosis
What is the SMV projection of the skull used to visualize?
Floor of the cranium (*common for suspected basal skull fractures)
Certain regions where sutures join are slow in their ossification after birth, these areas are known as _______.
Fontanels
The large opening at the base of the occipital bone through which the spinal cord passes as it leaves the brain
Foramen Magnum
What sinuses are demonstrated on the PA (Caldwell) radiograph?
Frontal & anterior ethmoid
What bones does the ethmoid articulate with?
Frontal & sphenoid, as well as 11 facial bones
This bone contributes to the formation of the forehead & the superior part of each orbit
Frontal bone
What is visualized on a PA 0 degree CR projection of the skull?
Frontal bone
What is visualized on a PA axial (Caldwell) projection of the skull?
Frontal bone
On each side of the squamous portion of the frontal bone above the SOG is a larger, rounded prominence known as the _________.
Frontal tuberosity(eminence)
What 3 bones make up the circumference or circular base of each orbit?
Frontal, zygoma, & maxilla
Connects the glabella to a point @ the anterior aspect of the alveolar process of the maxilla
GAL - glabelloalveolar line
Line between glabella & EAM
GML - glabellomeatal line
_______ is a smooth, raised prominence between the eyebrows just above the bridge of the nose.
Glabella
________ extend laterally from the sides of the body of the sphenoid & form a portion of the floor of the cranium, as well as a portion of the sides of the cranium.
Greater wings
Line that connects the IOM to the EAM
IOML - infraorbitomeatal line (*also known as Reid's base line or anthropologic base line)
Where do the sphenoid sinuses lie?
In the body of the sphenoid bone directly below the sella turcica
If the orbital floors are of interest, what would you do to modify the PA axial (Caldwell) projection of the facial bones?
Increase the CR angle to 30 degrees caudad to project the petrous ridges below the IOM
2 platelike, curved (or scroll-shaped) facial bones that project from the lateral walls of the nasal cavity on each side & extend medially
Inferior nasal conchae
________is the prominent bump or protuberance at the inferoposterior portion of the skull.
Inion (external occipital protuberance)
An opening in the temporal bone that serves as a passageway for nerves of hearing & equilibrium
Internal acoustic meatus
A line that connects the pupils or outer canthi of the eyes & is used to place the patient's head in a true lateral position for lateral projections involving the skull
Interpupillary line (IPL)
Line from the junction of the lips to the EAM
LML - lips-meatal line
What bones are the thinnest & most fragile bones in the entire body?
Lacrimal & nasal bones
_______ are 2 small delicate bones that lie anteriorly on the medial side of each orbit just posterior to the frontal process of the maxilla.
Lacrimal bones
What suture separates the 2 parietal bones from the occipital bone?
Lambdodial suture
What are the routine projections for the sinuses?
Lateral, PA (Caldwell), & Water's
What routine projections should be preformed for a study of the facial bones?
Lateral, Parietoacanthial (Water's Method), & PA axial (Caldwell Method)
The smaller pair of wings of the sphenoid that are triangular & nearly horizontal, & end medially in the 2 anterior clinoid processes
Lesser wings
Where are the petrous pyramids projected on the 15 degree CR Caldwell projection?
Lower 1/3 of the orbits
Connects the mental point to the EAM
MML - mentomeatal line
The largest facial bone that is the only movable bone in the adult skull.
Mandible
What should be visualized on a Water's projection of the facial bones?
Maxillae, zygomas, & bony nasal septum
What sinuses are demonstrated on a Water's radiograph?
Maxillary
What sinuses are present @ birth?
Maxillary
List the 4 paranasal sinuses
Maxillary (2) Frontal (2) Ethmoid (many) Sphenoid (1 or 2)
_______ are the only sinuses that are part of the facial bone structure, the others are contained within the respective cranial bones.
Maxillary sinuses
Located on each half of the body of the mandible are passageways for the mental artery, vein & nerve that innervate the lower lip and chin
Mental foramina
The center of the mental protuberance is referred to as the _______.
Mental point
The flat triangular area below the symphysis, marked by 2 knoblike protuberances that project forward is the ________.
Mental protuberance
What skull morphology falls under the description of the width of the skull being 75-80% of the length of the skull?
Mesocephalic(angle between the petrous pyramids & the MSP is 47 degrees)
Cranial sutures generally do not completely ossify until what age?
Mid-to-late 20s (some may not completely close until the 5th decade of life)
Portion of the lateral rim of the orbit that is near the outer canthus of the eye
Midlateral orbital margin
What is the special projection for facial bones?
Modified Parietoacanthial (Modified Water's)
What special projection of the facial bones can be used to visualize the orbits in their entirety to see if a "blowout" fracture has occurred?
Modified Parietoacanthial (Modified Water's) Projection
The 2 fused bones that form the bridge of the nose & are variable in size
Nasal bones
The pterygoid processes form part of the lateral walls of the _______.
Nasal cavities
Symmetric appearance of petrous ridges on an AP axial Towne's radiograph indicates what?
No rotation
Line between the outer canthus & the EAM
OML - orbitomeatal line
The inferoposterior portion of the calvarium is formed by the ________.
Occipital bone
What is being visualized on an AP axial (Towne) projection of the skull?
Occipital bone
What is visualized on a PA axial (Haas) projection?
Occipital bone
The ________ on each side of the orbital/horizontal portion of the frontal bone, forms the superior part of each orbit.
Orbital plate (level of SOG)
What is visualized on a PA axial (Caldwell) projection of the facial bones?
Orbits & bony nasal septum
What projection would you do instead of the PA 0 degree CR projection if the condyloid processes of the mandible were of interest?
PA axial (20-25 degree cephalad CR centered to exit @ the acanthion) projection
What is an alternative projection for patients who cannot flex their neck sufficiently for the AP axial (Townes)?
PA axial (Haas Method)
Bones that are roughly L-shaped w/ their vertical portion extending up between one maxilla & one pterygoid plate of the sphenoid, & their horizontal portion making up the posterior portion of the hard palate.
Palatine bones
Large, air-filled cavities that are sometimes called the accessory nasal sinuses because they are continuous with the nasal cavity
Paranasal sinuses
What is visualized on the Lateral projection of the skull?
Parietal & Temporal bone of side closest to the IR (sella turcica & dorsum sellae are seen in profile)
What is the routine for nasal bones?
Parietoacanthial (Water's Method) & both Laterals
Beneath the floor of the cranium projecting downward from the midline of the ethmoid bone is the ________, which helps form the bony nasal septum.
Perpendicular plate
The upper border or ridge of the petrous pyramids is commonly called the _______.
Petrous ridge (petrous apex)
What do you do if the patient is unable to depress their chin sufficiently enough to bring the OML perpendicular to the IR for an AP axial (Towne's)?
Place the IOML perpendicular to the IR instead & use a 37 degree caudad CR angle.
________ extend superiorly from the Dorsum sellae.
Posterior clinoid processes
Where do the frontal sinuses lie?
Posterior to the glabella
The medial pterygoid processes end inferiorly in hooklike processes known as what?
Pterygoid hamuli
The _______ are points posterior to the ear where the Squamousal & lambdodial sutures meet.
R. & L. Asterions
The _______ are points @ the junction of the parietals, temporals, & greater wings of the sphenoid.
R. & L. Pterions
________ are complex structures that house the delicate organs of hearing & balance.
R. & L. Temporal bones
What are the 2 most common positioning errors associated w/ skull radiography?
Rotation & tilt
What are the special projections of the sinuses?
SMV & Parietoacanthial transoral (open mouth Water's)
What is the special projection for the mandible?
SMV projection
What is the positioning routine for the Zygomatic Arches?
SMV, Oblique Inferosuperior (tangential), AP axial (Towne), & Parietoacanthial (Water's)
What suture separates the 2 parietal bones in the midline?
Sagittal suture
What is demonstrated on a Schuller Method radiograph?
Same as Modified Law
________ is a central depression on the body of the sphenoid bone that partially surrounds & protects the pituitary gland.
Sella turcica
The single centrally located ________ forms the anchor for all 8 cranial bones.
Sphenoid bone
What sinuses are demonstrated on an open mouth Water's radiograph?
Sphenoid sinuses visualized through the open mouth
The external surface of the occipital bone presents a rounded part called the _______.
Squamous portion
What sutures separate the 2 parietal bones from their respective temporal bones?
Squamousal sutures
Projecting inferior to the mandible & anterior to the EAM is a slender bony projection called the _______.
Styloid process
What are the special projections for the skull?
Submentovertex (SMV) PA axial (Haas)
Ridge or arch of bone that extends across the forehead directly above each eye
Superciliary ridge (arch)
The ________ are scroll-shaped projections of bone that extend medially & downward from the medial wall of each labyrinth.
Superior & medial nasal conchae (turbinates)
_________ is a slight depression above each eyebrow.
Supraorbital Groove (SOG) - corresponds to the floor of the anterior fossa & level of the orbital plate
The superior rim of each orbit is the _________.
Supraorbital Margin (SOM)
Slight groove or depression above the superciliary ridge that corresponds to the highest level of the facial bone mass
Supraorbital groove (SOG)
_________ is a small hole/opening within the SOM where the orbital nerve & artery pass through.
Supraorbital notch (foramen)
What are the breathing instructions for all cranium, facial, & sinus projections?
Suspended respiration
The body of the mandible units @ the anterior midline @ a union known as the _______.
Symphysis (symphysis menti)
What is the classification, mobility type, & movement type of the temporomandibular joint (TMJ)?
Synovial, diarthrodial, bicondylar
What positioning landmark corresponds to the highest level of the petrous ridges
TEA
What important external landmark do the petrous ridges of the petrous pyramids correspond to?
TEA (top of the ear attachment)
Inferior to the zygomatic process & anterior to the EAM is the ________, into which the mandible fits to form the TMJ.
Temporomandibular fossa
What should the mandible be "housing" on a Water's projection of the facial bones?
The Odontoid(dens) of C2
The horseshoe shape of the mandible is well visualized on what projection?
The SMV projection
What does the SMV mandible projection demonstrate?
The arch of the mandible
When the mouth is opened widely, where is the head of the condyloid process located in relation to the TM fossa?
The condyle moves forward to the front edge of the fossa
The upper portion of the ramus terminates in a U-shaped notch known as what?
The mandibular notch
What is the point of junction of the 2 nasal bones with the frontal bone known as?
The nasion
The sphenoid bone also has another foramen in it that forms an opening into the orbit known as ________.
The optic foramen
Small cartilaginous flap that covers the opening of the ear
Tragus
True/false: Below the orbital plates lie facial bones, & above the orbital plates is the anterior part of the floor of the brain case.
True
True/false: Certain small, irregular bones called sutural or wormian bones sometimes develop in adult skull sutures.
True
True/false: Demformity of the sella turcica is often the only clue that a lesion exists intracranially as seen radiographically.
True
True/false: Lesions that can cause erosion of the foramina of the greater wing can be detected radiographically.
True
True/false: Radiographic projections of the paranasal sinuses should preformed w/ a horizontal x-ray beam w/ patient in an erect position, if possible, to delineate air-fluids levels.
True
True/false: The petrous ridges fill the orbits up to the level of the SOM on the PA 0 degrees projection of the skull.
True
True/false: The posterior extension of the IOML approximates the location of the inion.
True
True/false: The squamous portion of the temporal bone is quite thin & is the most vulnerable portion of the entire skull to fracture.
True
______ is a single thin, triangular bone that forms the inferoposterior part of the nasal septum.
Vomer
The 3 pairs of nasal conchae divide the nasal cavities into various compartments that ________ incoming air before it reaches the lungs.
Warm & clean
What facial bones form the prominence of the cheeks & make up the lower outer portion of the orbits?
Zygomatic (malar) bones
