Osteology Of Skull Flashcards
(138 cards)
1
Q
What are the 2 parts of the skull
A
Neurocranium and viscerocranium
2
Q
What is neurocranium
A
The bony covering of the brain and the membranous covering (the cranial meninges)
3
Q
Contents of the neurocranium
A
Proximal part of the cranial nerves and vasculature of the brain
4
Q
The 2 Parts of the neurocranium
A
- A dome-like roof called the calvaria or skull cap
- A floor or cranial base called the basicranium.
5
Q
In adults the neurocranium is formed by how many bones
A
8 (four singular bones and two bilateral paired bones)
6
Q
What are the 8 bones of the neurocranium
A
Singular (SOFE)
-Sphnenoidal
-Occipital
-Frontal
-Ethmoidal
Bilaterally paired (PT)
-Parietal
-Temporal
7
Q
Viscerocranium comprises of what bones
A
Fascial bones (forms the anterior part of the cranium). It consists of bones surrounding the mouth (upper and lower jaw), nasal cavity and most of the orbits (eye sockets or orbital cavities).
8
Q
How many bones make up the viscerocranium
A
15 irregular bones (3 are singular and 6 are bilaterally paired)
9
Q
What are the 3 singular viscerocranium bones
A
VEM
- Vomer
- Ethmoidal
- Mandible
10
Q
What are the 6 bilaterally paired viscerocranial bones
A
My Inner Zip Pointed Lateral North
1. Maxillae
2. Inferior nasal conchae
3. Zygomatic
4. Palatine
5. Lacrimal
6. Nasal bones
11
Q
What viscerocranial bones house the teeth
A
Maxillae and mandible
12
Q
What viscerocranial bone forms the greatest part of the upper fascial skeleton, forms the skeleton of the upper jaw and is fixed to the cranial base
A
Maxillae
13
Q
What forms the skeleton of the lower jaw
A
Mandible
14
Q
Why is mandible moveable
A
Because it articulates with the cranial base at the temporomandibular joints (TMJs)
15
Q
What makes up the anterior or frontal or fascial part of the
A
Frontal bone, zygomatic bones, orbits, nasal region, mandible and maxillae
16
Q
What bones do the frontal bone articulate with
A
Nasal, zygomatic, ethmoid, sphenoid, lacrimal.
17
Q
The alveolar process of the maxillae includes
A
The tooth sockets called the alveoli and it houses the maxillary teeth.
18
Q
What bones do the maxillary bones articulate with anteriorly and laterally
A
Frontal bone and zygomatic bone
19
Q
Shape of the mandible
A
U-shaped
20
Q
The alveolar process of the mandible supports the
A
Mandibles teeth
21
Q
The 2 parts of the mandible
A
Body (horizontal part)
Ramus (vertical part)
22
Q
Location of the mental foramina
A
Inferior to the 2nd premolar teeth
23
Q
What passes through the mental foramina
A
Mental nerves and vessels
24
Q
Infraorbital foramen is located where and what passes through it
A
On the maxilla
Infraorbital nerve and vessel
25
What passes the supraorbital foramen
Supraorbital nerves and vessels
26
What passes the zygomaticofascial foramen
Zygomaticofascial nerve
27
What is injury to the supercilliary arches
Check slide
28
What is malar flush
Check slide
29
The superior aspect of the skull is called
Calvaria or skull cap
30
What are the bones forming the e superior part of the skull
Frontal bone (unpaired)
Parietal bone (paired)
Occipital bone (unpaired)
31
The frontal bone articulates with the parietal bones at the what
Coronal suture
32
The two parietal bones articulate with each other at what suture
Sagittal suture
33
The parietal bones articulate with the occipital bone at what suture
Lambdoid suture
34
The most superior part of the skull that is near to the midpoint of the sagittal bone is what
Vertex
35
The intersection between the CoronAl suture and the sagittal suture is called
Bregma
36
The junction between the sagittal suture and the lambdoid suture is called the
Lambda
37
What passes the parietal foramen on the parietal bones
Emissary veins
38
The region of the skull between the two parietal foramina where the closure of the sagittal suture usually begin
Obelion
39
What is depressed fracture of the calvaria
Check your slide
40
What is the most frequent type of calvarial fracture
Linear calvarial fracture
41
Types of calvarial fracture
Depressed fracture
Linear calvarial fracture
Comminuted fracture
Contrecoup or countercoup fracture
Basilar fracture
42
Obliteration of fracture begins at where
Bregma and continues sequentially in the sagittal, coronal and lambdoid suture
43
Obliteration of the sutures between bone of the calvaria begin between what age
Begins at age 30 and 40 years on the internal surface and approximately 10 years later on the external surface
44
The halves of the frontal bone of a new born is separated by
Frontal suture
45
The frontal and parietal bones of a new born are separated by
Coronal suture
46
The maxillae of a newborn baby are separated by
Intermaxillary suture
47
The two halves of the mandible of a new born are separated by
Mandibular symphysis
48
The mandible of a newborn begins fusion during ————— year and ends at what year ———-
1st year
2nd year
49
At birth, there is mastoid and styloid process. True or false
False
50
The mastoid process gradually forms at what year
1st year
51
What are frontanelles
They are membranous intervals that separates the bones of the calvaria of a newborn infant
52
How many frontanelles are present during infancy; name them
6
Posterior
Anterior
Paired sphenoidal
Paired mastoid frontanelles
53
What is the largest frontanelle
Anterior frontanelle
54
What is the shape of the anterior frontanelle
Diamond or star shaped
55
Why are the boundaries of the anterior frontanelle
Anteriorly by: two halves of the frontal bone.
Posteriorly: parietal bones.
56
Location of the anterior frontanelle
Junction of sagittal, coronal and frontal sutures (the future Bregma).
57
When does the anterior frontanelle close
18th month of age (the surrounding bones have fused and the anterior frontanelle os not clinically palpable)
58
When does the frontal bone begin to fuse
In the 2nd year
59
When is the frontal suture obliterated
The 8th year
60
In ~ 8% of people, the remnant of the frontal suture persists an what?
Metopic suture
61
What is the shape of the posterior frontanelle?
Triangular shape
62
Boundary of the posterior frontanelle
Anteriorly: the parietal bones
Posteriorly: the occipital bone
63
Location of the posterior frontanelle
The junction of the lambdoid and sagittal suture (future lambda).
64
When does the posterior frontanelle close
Begins closure during the first few months after birth and the 1st year. It’s small and no longer clinically palpable.
65
Location of the sphenoid and mastoid fontanelles
Overlain the temporal muscle
66
When does the sphenoid and the mastoid frontanelle fuse
During infancy
67
The two maxillae and nasal bones usually don’t fuse. True or false
True
68
What makes the calvaria of cranial bones change shape (mold) during child birth?
The softness of their cranial bones and the loosed connections at their sutures and frontanelles.
69
What happens to the calvaria during the passage of fetus through the birth canal?
The frontal bone becomes flat, the occipital bone is drawn out and the parietal bones slightly overrides the other.
70
What allows the cranial bones resist forces that would produce fractures in the adults
The resilience of the cranial bone
71
When does the shape of the calvaria return back to normal after undergoing molding.
Few days after birth
72
What permits the calvaria to enlarge during infancy and childhood
The fibrous suture
73
The increase in the size of the calvaria is greatest at what age
During the first two years of life (the period of the most rapid brain development).
74
The normal capacity of the calvaria increases for how many years
15-16 years
75
After the increase is size of the calvaria after the first 2 years then the next 15-16 years, the calvaria usually increase in size for another 3-4 years because of what
Bone thickening
76
What is craniosynostosis
Premature closure of the cranial sutures
77
Premature closure of the sagittal suture (in which the anterior frontanelle is small and results in a long wedge-shaped cranium) leads to
Scaphocephaly
78
Premature closure of the coronal or lambdoid suture (occurs in one side only) results in
Plagiocephaly
79
Premature closure of the coronal suture results in a high,,tower-like cranium called
Oxycephally or turricephaly
80
Oxycephaly or turricephaly is most common in
Females
81
Premature closure of the sutures usually don’t affect brain development, True or false
True
82
Composition of the lateral part of the neurocranium
Frontal, parietal, temporal, occipital and sphenoid.
83
What are the bones forming the visible part of the facial or viscerocranial
Zygomatic, nasal, mandible and maxillae
84
What are the of main features of the neurocranium
Temporal fossa, external auditory meatus and mastoid process of temporal bone.
85
What are the main features of the viscerocranium.
Infratemporal fossa, zygomatic arch, lateral aspect of mandible and maxilla
86
Where is the pterion on
The junction where the frontal, parietal, temporal and greater wing of sphenoid bone meet. It’s usually indicated by a H-shaped formation of sutures
87
Why is pterion area on important?
Because it overlies the middles meninges artery
88
What happens when the pterion becomes fractured
It can rupture the anterior branch of the middle meningeal artery which can lead to hematoma and this hematoma can exert pressure on the underlying cerebral cortex. If the rupture is left untreated, it can cause hemorrhage and lead to death in a few hours.
89
Boundaries of the infratemporal fossa
Superiorly: inferior surface of the greater wing of the sphenoid bone
Inferiorly: Superiorborder of the body of the mandible
Anteriorly: posterior surface of the maxilla.
Posteriorly: Styloid process and external auditory meatus
Laterally: zygomatic arch and ramus of mandible.
Medially: lateral pterygoid plate of the sphenoid bone.
90
The point where the superior temporal line cuts the coronal suture is called what
Stephanion
91
The junction (wheee they meet) between these three sutures: parietomastoid, occipitomastoid and lambdoid suture is called the
Asterion
92
What bones make up the posterior part of the skull
Occipital bone
Parts of parietal bones
Temporal bones(mastoid part)
93
The most prominent part of the external occipital protuberance is called the
Inion
94
What is the distance of the inferior Michael lines from the superior Michael lines
1 inch (2.5cm)
95
Along the lambdoid suture are what bones
Sutural or wormian bones
96
How many depressions/fossae do we have on the internal surface of the cranial base
3
Anterior, middle and posterior cranial fossae
97
Which cranial fossae is at the highest level and the shallowest
Anterior cranial fossa
98
What sits in the floor of the anterior cranial fossa
Frontal lobe of the cerebral hemispheres
99
What sits on the floor of the lateral portion of the middle cranial fossa
Temporal lobe
100
What sits on the midline of the middle cranial fossa
Pituitary gland or hypophysis
101
What is the lowest/ deepest part of cranial base
Posterior cranial fossa
102
What sits on the anterior portion of the floor of the posterior cranial fossa
Brainstem
103
Brainstem is made up of
Midbrain, pons and medulla oblongata
104
What occupies the rest of the posterior cranial fossa
Cerebellar hemispheres
105
The occipital lobe sits on the floor of the posterior cranial fossa. True or false
False
106
The cerebellum sits on the floor of the posterior cranial fossa. True or false
True
107
What bones forms the anterior cranial fossa?
Frontal bone in the anterior and lateral directions.
Ethmoidal bone in the middle
The 2 parts of Sphenoid bone in the posterior part
108
The part of the frontal bone in the anterior cranial fossa
Orbital surface
109
What are the two parts of sphenoid bone in the anterior cranial fossa
Jugum
Lesser wing of sphenoid
110
The cribiform plate of the Ethmoid bone has numerous tiny foramina that transmits what from the olfactory area of the nasal cavity to the olfactory bulb of the brain
Olfactory nerve (CN1)
111
What does the frontal cecum transmit (when open) from the nose to the superior sagittal sinus?
What is the clinical importance or this?
Emissary vein
Infections from the nose and other areas can be transmitted to the meninges and the brain.
112
What two structures passes through the optic canal as they exit the cranial cavity to enter the orbit?
Optic nerve (CN II) and ophthalmic artery.
113
The optic canals are usually included in the middle cranial fossa, true or false
True
114
What is the shape of the middle cranial fossa
Butterfly-shaped
115
What separates the anterior cranial fossa from the middle cranial fossa both laterally and centrally
Laterally: sphenoidal crest
Centrally: sphenoid limbus
116
What forms the posterior boundary of the jugum and anterior border of the prechiasmatic sulcus
Sphenoid limbus
117
Prechiamatic groove of bounded Posteriorly by
Tubercullum sella
118
What bones form the middle cranial fossa
Parts of the sphenoid bone
Parts of the temporal bone
119
The part of the sphenoid bone that forms the middle cranial fossa are
Sella turcica (part of the body of the sphenoid bone)
Greater wing of the sphenoid bone laterally
120
How many parts of sella turcica do we heave, name them
3
Tuberculum sella (anterior wall)
Hypophyseal fossa (houses the pituitary gland)
Dorsum sella (Posterior wall)
121
On each side of the body of the sphenoid are how many foraminas, name them?
4
Superior orbital fissure
Foramen rotundum
Foramen ovals
Foramen spinosum
122
What passes the superior orbital fissure
Cranial nerves III, IV, VI (occulomor, trochlear, abducens)
Ophthalmic division of trigeminal nerve (V1)
Ophthalmic vein
123
What passes the foramen rotundum?
Maxillary branch of trigeminal nerve (V2)
124
What passes through the foramen ovale
Mandibular branch of trigeminal nerve (V3)
Accessory meningeal artery
Lesser petrosal nerve
125
What passes through the foramen spinosum
Middle meningeal artery
Meningeal branch of mandibular nerve
126
What are the parts of the temporal bone that forms the middles cranial fossa
Squamous part laterally
Petrous part medially
127
What grooves are on the Petrous part is the temporal bone l.
Groove for greater and lesser Petrous mAl nerve
128
I life, foramenmlacerum is closed by the
A cartilage plate and The passage of some meningeal arterial branches and small veins
129
What forms the boundary between the middle and posterior cranial fossa?
Superior part of Petrous part of the temporal bone laterally and
Dorsum sellae (flat plate of bone) of the sphenoid bone medially.
130
Which is the largest of the 3 cranial fossa?
Posterior cranial fossa
131
What does the posterior cranial fossa lodge?
Brainstem (pons, midbrain and medulla oblongata)
132
What bones form the posterior cranial fossa
Occipital bone and temporal bone
133
The slope that extends from the Dorsum sella to the foramen magnum is called
The clivus
134
What passes through the internal acoustic meatus
CN VII and CN VII ( fascial and vestibulocochlear nerve)
135
What passes through the jugular foramen
CN IX- Glossopharyngeal nerve
CN X- Vagus nerve
CN XI- Accesory nerve
2 venous structures
1. The dura venous sinus from the posterior side of the sigmoid sinus .
2. The inferior Petrousal sinus from the anterior side of the sigmoid sinus
136
Fusion of the dura sinus and inferior petrousal sinus forms the
Internal jugular vein
137
What passes through the hypoglossal canal
Hypoglossal nerve CN XII
138
What passes through the foramen magnum?
-Spinal cord (which is continuous with the medulla oblongata
- Two vertebral arteries
- Spinal contribution of accessory nerve (spinal accessory nerve)
