Ch 11 Skull Flashcards by Michelle Niewinski

Which skull projections are used to see the frontal bones?

PA Axial (Caldwell method) 
PA projection

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Which projections are used to demonstrate the occipital bone?

AP Axial (Towne Method) 
PA Axial (Haas Method)

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What projection is used to demonstrate the parietal bones and entire cranium?

Lateral position

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Which position is used to demonstrate fractures (Tripod and le fort) and foreign bodies in the eye

Facial bones: waters Method

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What Method is used to see blowout fractures??

Modified waters (Facial bones) 
Demonstrated orbital floors

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Which position is used to demonstrate nasal bone fractures?

Lateral position of nasal bones 
Superinferior tangential (Axial) projection of nasal bones

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Which projection demonstrates the frontal sinuses?

PA Projection (Caldwell)

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Which projection is used to visualize maxillary sinus’s?

Waters Method of sinus
(Petronius ridges below sinus)
& open mouth waters

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Which projection shows the sphenoid sinus/ethmoid?

SMV of sinus

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What position causes the Petrous pyramids to be projected into the orbits??

PA Projection of Skull

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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

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OML -30* caudad or IOML -37*
Center 2 1/2 inches above glabella
Used to see occipital bone

AP Axial of skull

Towne Method

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Head in true lateral
IOML flexion
CR 2inches above EAM

Lateral position skull

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PA Axial (Caldwell Method) skull

Flex neck to OML
CR 15* caudad
Exits nasion

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PA Projection of skull

Flex neck OML
No angulation
Exits Glabella
To see frontal bone!

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Extend neck to IOML
CR to 1 1/2 inferior to mandible line
MSP
Center IR to CR

SMV

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Alternative projection to the Towne Method ??

Haas Method

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Haas Method

CR 25* cephalad
Flex neck to OML
Exit 1 1/2 inches above nasion

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Lateral position of facial bones

True lateral
IOML
CR to zygoma (cheek)
Midway between canthus and EAM

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Waters Method of Facial Bones

MML perpendicular and OML is 37* to table

CR MSP and exit Acanthion

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PA Axial Projection (Caldwell) facial bones

OML perpendicular
CR 15* caudad; exit nasion
Project Petronius ridge below iom

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(Modified waters) parietocanthial Projection (facial bones)

LML perpendicular
OML will be 55* with IR
Cr exits acanthion

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The highest level of the petroleum ridge is at the level of

The TeA

Top of ear

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Ther is an average distance between the OML and IOML that is

7-8 degrees

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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