Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account

Chapter 12 in Bontrager's radiographic positioning book.


Bony skeleton of head, rests on the superior end of vertebral column and is divided into two main sets.

Cranial and Facial Bones

What are the two sets of skull bones?


number of cranial bones


Numbr of facial bones

Calvaria (skull cap) bones

Frontal, right parietal, left parietal, and occipital.

Floor bones

Right temporal, left temporal, sphenoid, ethmoid.

Coronal suture

Lambdoidal suture

Lambdoidal suture

sagittal suture

squamosal suture

zygomatic arch

styloid process

Coronoid Process

EAM or External Acoustic Meatius

Mandibular Condyle

mastoid process

mental foramen

frontal bone

the bone of the calvaria that is most readily visible forms the forehead and the superior part of each orbit. Consists of two main parts

Squamous/Verticle and Orbital/Horizontal portion

Two main parts of the frontal bone.


Forms the forehead "portion"


Forms the superior "portion" of the orbit


the smooth, raised prominence between the eyebrows just above the bridge of the nose.

supraorbital groove (SOG)

slight depression above each eyebrow. Corresponds to the floor of the anterior fossa of the cranial vault.

orbital plate

The highest level of the facial bone mass

supraorbital margin (SOM)

the superior rim of each orbit

Supraorbital notch

Small hole or opening within the supraorbital margin slightly medial to its midpoint.

supraorbital nerve and artery

what passes through the supraorbital notch

frontal tuberosity (eminence)

located on each side of the squamous portion of the frontal bone above the supraorbital groove, its a large round prominence. AKA Forehead

orbital/horizontal portion

supraorbital margins, superciliay ridges, glabella, and frontal tuberosities.

orbital plate

Forms the superior part of each orbit. It is seperated by the ethmoidal noch.

right and left parietals, sphenoid, and ethmoid

the frontal bone articulated with what four cranial bones.

parietal bones

are rough and square and have a concave internal surface.

parietal tubercles (eminences)

Widest portion of entire skull is located between this

frontal, occipital, temporal, sphenoid, parietal

parietal bone articulation

occipital bone

forms the inferoposterior portion of the skull cap (calvaria).


external occipital protuberance is also known as


prominent bumb or protuberance at the inferoposterior portion of the skull

foramen magnum

large opening at the base of the occipital bone through which the spinal cord passes.

occipital condyles

lateral oval processes with convex surfaces with one on each side of the foramen magnum.


occipital condyle articulate with what depression on the c-spine?

atlantooccipital joint

two part articulation between the skull and the c-spine

2 parietals, 2 temporals, sphenoid, and the atlas

articulations of the occipital bone


1st cervical vertebrae

right and left temporal bones

structures that house the delicate organs of hearing and balance

zygomatic process

the arch that extends anteriorly from the squamous portion of the temporal bone

zygomatic arch

the zygomatic process meets the temporal process of the zygomatic bone to form the

temporomandibular fossa

sits inferior to the zygomatic process and anterior to the EAM, it forms the TMJ (temporomandibular joint)

styloid process

projecting inferior to the mandible and anterior to the EAM is a slender bony projection called,

Mastoid process

the second portion, posterior to the EAM

squamous portion

upper portion of temporal bone that forms part of the wall of the skull

petrous portion

the third main portion, most dense.

pars petrosa

aka petrous portion, or petrous pyramid

petrous pyramids

project anteriorly and toward the midline from the area of the EAM

petrous ridge

corresponds to the level of an important external landmark the TEA.

top of ear attachment


parietal, occipital and sphenoid

the temporal bone articulates with what three cranial bones:

sphenoid bone

centrally located, forms the anchor for all eight cranial bones

sella turcica

central depression on the body. Looks like a saddle from the side.

pituitary gland

this gland is protected by the sella turcica.

pituitary gland

the hypophysis cerebri is also known as

sella turcica

deformity of __________is often the only clue that a lesion exists intracranially.


depressions of the sella turcica and the dorsum sellae are best seen in this view


articulates with all seven of the other cranial bones

ethmoid bone

lies primarily below the floor of the cranium

cribriform plate

small upper horizontal portion of the ethmoid bone which contains many small openings or foramina through which segmental branches of the olfactory nerves pass.

crista galli

projecting superiorly from the cribriform plate, is derived for "rooster's comb".


articulates with two cranial bones: frontal and sphenoid


articulations or joints of the adult cranium


sutures are classified as __________ joints.


True or False: Sutures are fibrous/synarthrodial joints.


a synarthrodial joint is _______________

coronal suture

separates the frontal bone from the two parietal

sagittal suture

Separates the two parietal bones in the midline

lambdoidal suture

separates the two parietals from the occipital bone

squamosal sutures

formed by the inferior junction of the two parietal bones with their respective temporal bones


anterior end of the sagittal suture


posterior end of the sagittal suture


the right and left (pterions or asterions) points at the junction of the parietals, temporals, and the greater wings of the sphenoid


the right and left (pterions or asterions) are points posterior to the ear where the squamosal and lamdboidal sutures meet


regions in the infant cranium where suture join are slower in their ossification.

12-13 years old

when do cranial sutures ossify

soft spots

early in life the the bregma and the lambda are not bony but are membrane covered ______________


bregma in an adult is ________ fontanel in child


lambda in an adult is________ fontanel in child


right and left pterion in adult is right and left __________ fontanel in child


right and left asterion in adult is right and left ________ fontanel in child


the average head is classified as

parietal, frontal, occipital

a general rule for describing skull type is to compare the width of the skull at the _________ eminence with the length mesaused from the _______ eminence to the external _________ protuberance.


the average mesocephalic skull is 75% of (width or length)


the average mesocephalic skull is 80% of (width or length)


short, broad head is termed ________________


long, narrow head is termed ___________

80% or greater

the width of the brachycephalic type is _______ than the length

75% or less

the width on the long narrow dolicocephalic is ______ the length

angle difference

a second variation to remember is the ______ ________ between the petrous pyramid and the midsagittal plane.


in the average shaped, mesocephalic head, the petrous pyramid form an angle of ____ degrees.

greater than 47

in the brachycephalic skull, the angle is (greater than 47 or lesser than 47) degrees.

less than 47

in the dolichocephalic skull, the angle is (greater than 47 or lesser than 47) degrees.

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording