Ch 11 Skull Flashcards
Which skull projections are used to see the frontal bones?
PA Axial (Caldwell method) PA projection
Which projections are used to demonstrate the occipital bone?
AP Axial (Towne Method) PA Axial (Haas Method)
What projection is used to demonstrate the parietal bones and entire cranium?
Lateral position
Which position is used to demonstrate fractures (Tripod and le fort) and foreign bodies in the eye
Facial bones: waters Method
What Method is used to see blowout fractures??
Modified waters (Facial bones) Demonstrated orbital floors
Which position is used to demonstrate nasal bone fractures?
Lateral position of nasal bones Superinferior tangential (Axial) projection of nasal bones
Which projection demonstrates the frontal sinuses?
PA Projection (Caldwell)
Which projection is used to visualize maxillary sinus’s?
Waters Method of sinus
(Petronius ridges below sinus)
& open mouth waters
Which projection shows the sphenoid sinus/ethmoid?
SMV of sinus
What position causes the Petrous pyramids to be projected into the orbits??
PA Projection of Skull
The Petronius pyramids must be removed from facial bone area; by raising the chin, the Petronius pyramids are projected below maxillary sinus’ what Method allows this??
Parietocanthial (waters Method) Projection
OML -30* caudad or IOML -37*
Center 2 1/2 inches above glabella
Used to see occipital bone
AP Axial of skull
Towne Method
Head in true lateral
IOML flexion
CR 2inches above EAM
Lateral position skull
PA Axial (Caldwell Method) skull
Flex neck to OML
CR 15* caudad
Exits nasion
PA Projection of skull
Flex neck OML
No angulation
Exits Glabella
To see frontal bone!
Extend neck to IOML
CR to 1 1/2 inferior to mandible line
MSP
Center IR to CR
SMV
Alternative projection to the Towne Method ??
Haas Method
Haas Method
CR 25* cephalad
Flex neck to OML
Exit 1 1/2 inches above nasion
Lateral position of facial bones
True lateral
IOML
CR to zygoma (cheek)
Midway between canthus and EAM
Waters Method of Facial Bones
MML perpendicular and OML is 37* to table
CR MSP and exit Acanthion
PA Axial Projection (Caldwell) facial bones
OML perpendicular
CR 15* caudad; exit nasion
Project Petronius ridge below iom
(Modified waters) parietocanthial Projection (facial bones)
LML perpendicular
OML will be 55* with IR
Cr exits acanthion
The highest level of the petroleum ridge is at the level of
The TeA
Top of ear
Ther is an average distance between the OML and IOML that is
7-8 degrees
The GAL is located where
Glabelloalveloar line
The GAL connects the glabella and the anterior aspect of the alveolar process of the maxilla
(Used for Lateral Skull and tangential nasal bones)
the occipital protuberance
The widest portion of the skull
Inion
Parietal tubercles (eminence)
2 devices may be used to ensure accurate lining of the positioning lines which are:
A Straightedge
A ruler
The highest level of the facial bone mass
SOG
Same level as (Floor of anterior fossa )
The part of the external ear that is a large cartilagous flap outside the ear
Auricle or pinna
The small cartilaginous flap the covers the opening of the ear
The Tragus
Shape of average head is termed
Mesocephalic
Fracture of the floor of the orbit
A severe bilateral horizontal fracture of the maxilla
Blowout fracture
Le fort fracture
A hit on one side that results in a fracture on opposite side.
Contrecoup fracture
Ex:mandible is hit on one side but opposite side is fractured
Will we increase or decrease exposure for pituitary adenoma?
+ increase bcuz of smaller field size
A growth from mucous membrane hat projects into sinus cavity
A polyp
A benign tumor of the auditory nerve
Acoustic neuroma
Bacterial infection of the mastoid process
Acute mastoiditis
Also referred to as a ping pong fracture
Depressed fracture
A small hole located in the sphenoid is called and allows what?
Optic foramen
Allows optic Nerve to pass
Each orbit contains ____ bones.
The skull has 2 sets of bones cranial and facial. How many for each
7 bones
(3 cranial 4 Facial)
Cranial 8
Facial 14
Projecting inferior to mandible and anterior to EAM
Houses the organs of hearing and equilibrium
Styloid process
Petrous pyramid (pars petrosa)
Upper border of the petrous pyramid is called
Also corresponds to the level of TeA!
Petrous Ridge (petrous apex)
Each temporal bone articulated with 3 bones which are:
Parietal
OccipitAl
Sphenoid bones
The central depression of the body of sphenoid
(Looks like a saddle)
This protects a major gland of the body which is the
Sella turcica
Pituitary gland!!
Dorsum sella is the back of saddle!!
The sella turcica is located on the ______ bone to protect the _________ gland. It has anterior and posterior ______ processes and the posterior side is the dorsum sella
Sphenoid
Pituitary
Clinoid
The sella turcica and the dorsum sellae are best demonstrated on which projection
The lateral projection of cranium
The upper small horizontal portion of the ethmoid bone is called
(Which provides small opening for branches to olfactory nerves)
The cribriform plate!
Another name or derived from the “roosters comb” superior to the cribriform plate is the
Crista Galli
The lateral labrynths or masses are located downward from ethmoid to help form
Nasal bones
The sutures of our skull are articulations or joints that are classified as
Fibrous and synathrodial joints!!
Conjunction of 2 parietal bones
Separates parietal from occipital
Squamosal suture
Lambdoidal suture
The joining of sutures doesn’t occur til some time after birth called Fontanels!! The cranial sutures do not ossify until
Mid-late 20’s!!
Early in life the Bregma and Lambda are not bony (soft spots) these are called:
Fontanels
6occur in infant
3 main parts of the middle Ear
Tympanic membrane
Auditory ossicles
Tympanic cavity
The passageway between the middle ear and the nasopharynx
Eustachian tube
3 small bones of the middle ear
Beginning of the ear
Auditory ossicles
Tympanic membrane
Vibrations are first picked up by the ____ meaning “hammer”
Malleus
Each nasal bone articates with
2 cranial bones and 2 facial bones
Which auditory ossicle is the smallest?
Which resembles premolar?
Stapes
Incus
New and abnormal growth:
Expansion of internal acoustic canal:
The EAM is how long?
Neoplasia
Acoustic neuroma
1inch
4 processes of maxilla
Frontal
Zygomatic
Alveolar
Palatine
A free floating zygomatic bone is also called__________ fracture
Tripod
What facial bones are best seen with the parietocanthial projection?
Orbits
For the Caldwell projection, the 30* angle is used to put the _________ below the orbit floor
Petrous ridges
2 reasons the facial bones are done PA rather than AP?
Decrease OID,
Decrease exposure
Lateral projections for nasal bones are usually taken_______
Bilaterally
To demonstrate the sinuses, and obtain air-fluid levels, it is important to
Perform erect
Use horizontal beam
To rule out sinusitis in the maxillary sinuses, what other modality may be used??
Ultrasound
Which sinuses are best demonstrated with a PA Caldwell?
Frontal and anterior ethmoid bones
Which projection best demonstrates the maxillary sinus?
Waters projection
Placing petrous ridge below them
A lateral radiograph shows the greater wings of sphenoid are NOT superimposed; what positioning error was done?
Rotation of the skull
Which single projection may be used for facial bones for any possible air fluid levels of patient can’t stand or sit erect?
Horizontal beam
The sphenoid sinus lie directly inferior to:
Which aspect of ethmoid bones contain air cells?
Sella turcica
Lateral masses
A lateral projection shows that the orbital plates are not superimposed; what positioning error is this?
Tilt
In an AP Towne, The left petrous ridge is wider than the right; why positioning error is this?
Rotation of skull to patients R
Which 2 projections place the dorsum sellae into the foramen magnum ?
Towne
HAAS
Which auditory ossicle attaches to the oval window?
Serious brain infection:
Stapes
Encephalitis
The thinnest part of the temporal bone and the frontal bone?
Squamous portion
The most lateral aspect of the middle ear ?
Another name for Reid’s Baseline?
Malleus
IOML
2 terms for small, irregular bones on the adult skull sutures
Wormian or sutural
The Calvarium (skullcap) consists of which 4 bones?
Frontal bone
Both L and R parietal bones
Occipital bone
The floor of the skull is made up of which 4 bones ?
R and L temporal bones
Sphenoid
Ethmoid
May demonstrate enlarged sella turcica and erosion of dorsum sella; CT and MRI are mostly used.
Pituitary adenomas
Fractures through dense inner structure of temporal bones; can cause bleeding into sphenoid sinus
Basal Skull fracture
What projection projects petrous pyramids directly into orbits?
PA Skull Projection
For the waters method; where should the petrous pyramids lie??
Below the maxillary sinuses
For an AP Towne, where should the dorsum sellae be visualized?
Inside the foramen magnum
For the superoinferior tangential Axial Projection of nasal bones; where should Cr be ?
CR to nasion and ensure it is parallel to GAL
