Ch. 11 Skull Flashcards
(104 cards)
1
Q
the skull is divided into these two sets of bones, how many are in each
A
8 cranial bones
14 facial bones
2
Q
the bones of the cranium are divided into these two sections
A
- calvarium (skullcap)
- floor
3
Q
what are the bones of the floor of the skull
A
- right temporal
- left temporal
- sphenoid
- ethmoid
3
Q
what are the bones of the calvarium (skullcap)
A
- frontal
- left parietal
- right parietal
- occipital
3
Q
what are the two main parts of the frontal bone
A
- squamous/vertical portion
- orbital/horizontal portion
4
Q
this main part forms the forehead
A
squamous/vertical portion
5
Q
this main part forms the superior part of the orbit
A
orbital/horizontal portion
6
Q
smooth, raised prominence between the eyebrows just above the bridge of the nose
A
glabella
7
Q
slight depression above each eyebrow
A
supraorbital groove (SOG)
8
Q
the supraorbital groove (SOG) corresponds to what
A
floor of the anterior fossa of the cranial vault
9
Q
what is the supraorbital groove (SOG) also at the level as
A
orbital plate (highest level of the facial bone mass)
10
Q
superior rim of each orbit
A
supraorbital margin (SOM)
11
Q
small hole or opening within the SOM slightly medial to its midpoint
A
supraorbital notch (foramen)
12
Q
what passes through the supraorbital notch
A
supraorbital nerve and artery
13
Q
on each side of the squamous portion of the frontal bone above the SOG is a larger, rounded prominence called what
A
frontal tuberosity (eminence)
14
Q
what does the orbital/horizontal portion of the frontal bone consist of
A
- supraorbital margin (SOM)
- superciliary ridges
- glabella
- frontal tuberosities
15
Q
forms the superior part of each orbit
A
orbital plate
16
Q
each orbital plate is separated from the other by this
A
ethmoidal notch
17
Q
what bones do the frontal bone articulate with
A
4 cranial bones
- R and L parietals
- sphenoid
- ethmoid
(8 facial bones)
18
Q
the lateral walls of the cranium and part of the roof are formed by these bones
A
parietal bones
19
Q
these bones are roughly square and have a concave internal surface
A
parietal bones
20
Q
where is the widest portion of the entire skull located
A
between parietal tubercles (eminences) of the parietal bones
21
Q
where are the greater wings of the sphenoid located in relation to the parietals
A
inferior and anterior
22
Q
what bones do the parietals articulate with
A
5 cranial bones
- frontal
- occipital
- temporal
- sphenoid
- opposite parietal
23
the inferoposterior portion of the calvarium is formed by this
occipital bone
24
the external surface of the occipital bone presents a rounded part called what
squamous portion
25
prominent bump or protuberance at the inferoposterior portion of the skull
occipital protuberance, or inion
26
forms most of the back of the head and is the part of the occipital bone that is superior to the external occipital protuberance, or inion
squamous portion
27
the large opening at the base of the occipital bone through which the spinal cord passes as it leaves the brain
foramen magnum
28
oval processes with convex surfaces, with one on each side of the foramen magnum
two lateral condylar portions (occipital condyles)
29
what is the two part articulation between the skull and the cervical spine called
atlantooccipital joint
30
what type of joints are the atlantooccipital joints
ellipsoidal joints
31
what bones does the occipital bone articulate with
6 bones
- 2 parietals
- 2 temporals
- sphenoid
- atlas
32
complex structures that house the delicate organs of hearing and balance
temporal bones
33
what are the temporal bones situated between
- greater wings of sphenoid anteriorly
- occipital bone posteriorly
34
extending anteriorly from the squamous portion of the temporal bone is an arch of bone called what
zygomatic process
35
the zygomatic process meets the temporal process of the zygomatic bone to form this
zygomatic arch
36
inferior to the zygomatic process and just anterior to the external acoustic (auditory) meatus (EAM) is what
temporomandibular (TM) fossa
37
projecting inferior to the mandible and anterior to the EAM is a slender bony projection called what
styloid process
38
how many sections is the temporal bone divided into
3 primary parts
- squamous
- mastoid
- petrous
39
thin upper portion of the temporal bone that forms part of the wall of the skull; quite thin and most vulnerable portion of the entire skull to fracture
squamous portion
40
most vulnerable portion of the entire skull to fracture
squamous portion of the temporal bone
41
area posterior to the EAM
mastoid portion
42
many air cells are located within this process
mastoid process
43
portion of the temporal that houses the organs of hearing and equilibrium
petrous portion (petrous pyramid; pars petrosa)
44
the upper border or ridge of the petrous pyramids is commonly called what
petrous ridge (petrous apex)
45
thickest and densest bone in the cranium
petrous portion of the temporal bone
46
these project anteriorly and toward the midline from the area of the EAM
petrous pyramids
47
the petrous ridge of the petrous pyramids corresponds to the level of what important external landmark
TEA (top of the ear attachment)
48
near the center of the petrous pyramid on the posterior surface just superior to the jugular foramen is an opening/orifice called what; serves to transmit the nerves of hearing and equilibrium
internal acoustic meatus
49
these are located at the base of the cranium and are where the internal jugular veins are formed and 3 cranial nerves (IX, X, XI) pass
bilateral jugular foramina
50
what bones do each temporal bone articulate with
3 cranial bones
- parietal
- occipital
- sphenoid
(2 facial bones)
51
this bone forms the anchor for the other 7 cranial bones
sphenoid bone
52
central portion of the sphenoid bone which lies in the midline of the floor of the cranium and contains the sphenoid sinus
body
53
the central depression on the body of the sphenoid bone
sella turcica
54
the sella turcica partially surrounds and protects what major gland of the body
hypophysis cerebri (pituitary gland)
55
posterior to the sella turcica, the back of the saddle
dorsum sellae
56
shallow depression that begins on the posteroinferior aspect of the dorsum sellae of the sphenoid bone and extends posteriorly to the foramen magnum at the base of the occipital bone
clivus
57
the clivus forms a base of support for what
pons and basilar artery
58
the lesser wings of the sphenoid bone end medially with what
anterior clinoid processes
59
these project laterally from the superoanterior portion of the body of the sphenoid and extend to the middle of each orbit
lesser wings
60
these extend laterally from the sides of the body of the sphenoid and form a portion of the floor of the cranium and a portion of the sides of the cranium
greater wings
61
how many foramina exist in the greater wings of the sphenoid for cranial nerves
3 pairs (6 total)
62
what are the names of the 3 pairs of foramina on the greater wing of the sphenoid from anterior to posterior
- foramen rotundum
- foramen ovale
- foramen spinosum
63
which clinoid processes are larger and spread farther apart
anterior clinoid processes
64
these extend superiorly from the dorsum sellae
posterior clinoid processes
65
between the anterior body and the lesser wings of the sphenoid on each side are groove like canals, the canals begin in the center as what
chiasmatic or optic groove
66
the chiasmatic or optic groove leads on each side to what
optic canal
67
what does the optic canal end at
optic foramen (opening in the orbit)
68
slightly lateral and posterior to the optic foramina on each side are irregularly shaped openings called what
superior orbital fissures
69
what are the more lateral, flat extensions projecting downward from inferior surface of the body of the sphenoid called
lateral pterygoid processes
70
directly medial to the lateral pterygoid processes are these
medial pterygoid processes
71
the medial pterygoid processes end inferiorly in small hooklike processes called what
pterygoid hamuli
72
these form part of the lateral walls of the nasal cavities
pterygoid processes/plates
73
deformity of the sella turcica is often an indication of what
lesion exists intracranially
74
what imaging modality may be performed to detect deformity of the sella turcica
CT and MRI
75
what bones does the sphenoid articulate with
all 7 cranial bones
(5 facial bones)
76
what is the small upper horizontal portion of the ethmoid
cribriform plate
77
the cribriform plate contains many small foramina through which segmental branches of what pass through
olfactory nerves (nerves of smell)
78
projecting superiorly from the cribriform plate
crista galli
79
projecting downward in the midline of the ethmoid is this which helps to form the bony nasal septum
perpendicular plate
80
these are suspended from the undersurface of the cribriform plate on each side of the perpendicular plate
lateral labyrinths (masses)
81
these contain the ethmoid air cells or sinuses and help to form the medial walls of the orbits and the lateral walls of the nasal cavity
lateral masses
82
extending medially and downward from the medial wall of each labyrinth are thin, scroll-shaped projections of bone called what
superior and middle nasal conchae or turbinates
83
what bones does the ethmoid articulate with
2 cranial bones
- sphenoid
- frontal
(11 facial bones)
84
this forms the upper portion of the bony nasal septum
perpendicular plate
85
what are the articulations/joints of the cranium called
sutures
86
what type of joints are sutures
fibrous - synarthrodial (adult)
87
this separates the frontal bone from the two parietal bones
coronal suture
88
this separates the two parietal bones in the midline
sagittal suture
89
posteriorly, this separates the two parietal bones from the occipital bone
lambdoidal suture
90
inferior junctions of the two parietal bones with their respective temporal bones
squamosal sutures
91
what is the anterior end of the sagittal suture called
bregma
92
what is the posterior end of the sagittal suture called
lambda
93
points at the junction of the frontal, parietals, temporals, and greater wings of the sphenoid (posterior end of the sphenoparietal suture)
pterions
94
points posterior to the ear where the squamosal and lambdoidal sutures meet
asterions
95
certain regions where sutures joining are slower in ossification are called what
fontanels
96
when do cranial sutures ossify completely
mid-late 20s (sometimes 5th decade of life)
97
these are termed the anterior and posterior fontanels in infants
bregma and lambda
98
which is the largest fontanel and how big is it at birth
anterior fontanel
1" wide, 1.5" (4cm) long
99
when does the anterior fontanel completely close
18 months
100
what are the 2 smaller fontanels that close soon after birth
sphenoid (pterion)
mastoid (asterion)
101
certain small, irregular bones sometimes develop in adult skull sutures called what
sutural/wormian bones
102
where are sutural/wormian bones most often found
lambdoidal suture (occasionally in regions of the fontanels especially posterior)
