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113 terms

Radiology: Skull

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.