The Skull Flashcards
1
Q
The Skull
- Composed of ___ bones
A
22
2
Q
Neurocranium: (4)
A
o bony case of the brain and cranial meninges
o made of 8 bones
o 4 singular bones centred on the midline
3
Q
What are the 4 singular bones centred on the midline on the neurocranium?
A
- Frontal
- Ethmoid
- Sphenoid
- Occipital
4
Q
What are the 2 sets of bones occurring bilaterally on the neurocranium?
A
- Temporal
- Parietal
5
Q
Viscerocranium: (3)
A
o Makes up the facial skeleton
o Consists of 14 bones
o 2 singular bones centred on the midline
6
Q
What are the 2 singular bones centred on the midline on the viscerocranium?
A
- Mandible
- Vomer
7
Q
What are the 6 sets of bones occurring bilaterally?
A
- Maxillae
- Inferior nasal conchae
- Zygomatic
- Palatine
- Nasal
- Lacrimal
8
Q
What are the Cranial Nerves? (15)
A
9
Q
Right lateral aspect of the skull:
A
10
Q
CN I:
A
Olfactory
11
Q
CN II:
A
Optic
12
Q
CN III:
A
Oculomotor
13
Q
CN IV:
A
Trochlear
14
Q
CN V:
A
Trigeminal
15
Q
CN V1:
A
Ophthalmic branch
16
Q
CN V2:
A
Maxillary branch
17
Q
CN V3:
A
Mandibular branch
18
Q
CN VI:
A
Abducens
19
Q
CN VII:
A
Facial
20
Q
CN VIII:
A
Vestibulocochlear
21
Q
CN IX:
A
Glossopharyngeal
22
Q
CN X:
A
Vagus
23
Q
CN XI:
A
Accessory
24
Q
CN XII:
A
Hypoglossal
25
What does the frontal bone form?
Forms the skeleton of the forehead
26
What does the frontal bone articulate with? (2)
* Articulates inferiorly with the nasal and zygomatic bones
* Also articulates with lacrimal, ethmoid and sphenoid bones
27
Frontal bone:
Supra-orbital foramen -
Supra-orbital foramen- passage for supra-orbital nerve and vessels
28
Frontal bone:
Super-ciliary arch-
Super-ciliary arch- prominence deep to the eyebrows
29
Frontal bone:
Glabella -
Glabella- smooth, slightly depressed area between the super-ciliary arches
30
Frontal bone:
Nasion -
Nasion- intersection between frontal and nasal bones
31
What are the Zygomatic bones? (3)
* Form the prominences of the cheeks
* Lie on the inferolateral sides of the orbits
* Rest on the maxillae
32
Zygomatic bones:
Zygomaticofacial foramen -
Zygomaticofacial foramen- pierces lateral aspect of the bone
33
What do the zygomatic bones articulate with?
Articulates with frontal, sphenoid, temporal bones and maxillae
34
Nasal region:
Piriform aperture-
Piriform aperture- pear-shaped anterior nasal opening in the cranium
35
Nasal region:
Bony nasal septum-
Bony nasal septum- made of ethmoid (perpendicular plate) superiorly and vomer inferiorly
36
Nasal region:
Nasal conchae-
Nasal conchae- curved bony plates on the lateral wall of each nasal cavity
37
Nasal region:
o The inferior nasal _____ is an independent bone
o Middle and superior nasal conchae are part of ______
concha
ethmoid
38
What do the Maxillae do?
Form the upper jaw
39
Maxillae:
Alveolar processes-
Alveolar processes- tooth sockets and supporting bone for maxillary teeth
40
Maxillae:
* Surround most of the ______ aperture
* Form the ______ margins medially
* Broad connection with zygomatic bones ________
piriform
infraorbital
laterally
41
Where are the 2 maxillae?
* The 2 maxillae are united at the intermaxillary suture in the median plane
42
Maxillae:
Infraorbital foramen-
Infraorbital foramen- inferior to each orbit for passage of infraorbital nerve and vessels
43
Mandible:
__-shaped bone
U
44
Mandible:
* ______- horizontal portion
* _____ - vertical portion
* Body- horizontal portion
* Ramus- vertical portion
45
Mandible:
Mental foramina-
Mental foramina- inferior to the 2nd premolar teeth for mental nerves and vessels
46
Mandible:
Mental protuberance-
Mental protuberance- forms the prominence of the chin inferior to the mandibular symphysis
47
Mandible:
Mandibular symphysis-
Mandibular symphysis- union of the halves of the infantile mandible
48
Lateral Aspect of Cranium:
1. External acoustic meatus opening:
* Entrance to the external acoustic meatus leading to the tympanic membrane
49
Lateral Aspect of Cranium:
2. Mastoid process of temporal bone:
* Postero-inferior to the external acoustic meatus opening
50
Lateral Aspect of Cranium:
3. Styloid process of temporal bone: (2)
* Anteromedial to the mastoid process
* Slender needle-like, pointed projection
51
Lateral Aspect of Cranium:
4. Zygomatic arch:
* Formed by the union of the temporal process of the zygomatic bone and the zygomatic process of the temporal bone
52
Lateral Aspect of Cranium:
5. Pterion:
* H-shaped formation of sutures that unite the frontal, parietal, sphenoid (greater wing) and temporal bones
53
Occipital Aspect of Cranium:
1. External occipital protuberance: (2)
* Easily palpable in the median plane
* Inion- a craniometric point defined by the tip of the protuberance
54
Occipital Aspect of Cranium:
2. External occipital crest:
* Descends from the external protuberance toward the foramen magnum
55
Occipital Aspect of Cranium:
3. Superior nuchal line: (2)
* Marks the superior limit of the neck
* Extends laterally from each side of the occipital protuberance
56
External Surface of Cranial Base:
1. The hard palate: (2)
* Formed anteriorly by the palatal processes of the maxillae
* Formed posteriorly by the horizontal plates of the palatine bones
57
External Surface of Cranial Base:
2. Posterior nasal spine:
* Projection of the free posterior border of the palatines posteriorly in the median plane
58
External Surface of Cranial Base:
3. Incisive foramen: (2)
* Posterior to the central incisor teeth
* Depression in the midline of the bony palate into which the incisive canals open
59
External Surface of Cranial Base:
4. Choanae (posterior nasal apertures): (2)
* Superior to the posterior edge of the palate
* Separated from each other by the vomer
60
External Surface of Cranial Base:
5. Vomer: (2)
* Flat, unpaired bone
* articulates inferiorly on the midline with the maxillae and the palatines, superiorly with the sphenoid via
its wings, and antero-superiorly with the ethmoid
61
6. Sphenoid:
* irregular unpaired bone with 3 pairs of processes:
o Greater wings- have orbital, temporal and infratemporal surfaces
o Lesser wings- originating superior to the greater wings
o Pterygoid processes- consist of lateral and medial pterygoid plates that extend inferiorly on each
side of the sphenoid from the junction of the body and the greater wings
62
What is the shape of the Palatine?
L-shaped paired bones making the posterior hard palate
63
How is the Perpendicular plate appressed?
* Perpendicular plate is appressed tightly to the maxilla anteriorly and between the pterygoid plates of sphenoid posteriorly
64
How does the palatine articulate? (VEI)
Articulate with vomer, ethmoid and inferior nasal conchae
65
Palatine:
Horizontal plate-
Horizontal plate- forms posterior third of the hard palate
66
The palatine has greater and lesser palatine_______.
foramina
67
How is the Anterior cranial fossa formed? (2)
* Formed by the frontal bone anteriorly, ethmoid bone in the middle and lesser wings and body of sphenoid posteriorly
* Frontal bone forms the roof of orbits and supports frontal lobe of the brain
68
* Ethmoid: (3)
o Cribriform plate- sieve-like portion lateral to the root of crista galli and roofs the nasal cavities
o Crista galli- interposed between olfactory bulbs and anchors falx cerebri posteriorly
o Perpendicular plate- forms superior nasal septum and articulates inferiorly with vomer
69
Middle cranial fossa
* Central part composed of:
sella turcica of sphenoid (pg. 5 diagram of sphenoid- superior view)
70
What is the middle cranial fossa surrounded by?
o Surrounded by anterior and posterior clinoid processes
71
Middle cranial fossa: (3)
- Tuberculum sellae- forms the anterior boundary of the hypophysial fossa
- Hypophysial fossa- median depression in the body of the sphenoid for the pituitary gland
- Dorsum sellae- square plate of bone projecting superiorly with posterior clinoid processes
72
How is the middle cranial fossa separated from the anterior cranial fossa?
* Separated from the anterior cranial fossa by the sharp posterior borders of the lesser wings of the
sphenoid bones that end medially as the anterior clinoid processes
73
Bones forming the lateral parts: (3)
o Greater wings of sphenoids
o Squamous parts of temporals laterally
o Petrous parts of temporals posteriorly
74
Separated from the posterior cranial fossa by: (2)
o The superior border of the petrous part of temporals laterally
o The dorsum sellae of the sphenoid medially
75
Posterior cranial fossa
* Houses: (3)
the cerebellum, pons and medulla oblongata
76
Posterior cranial fossa is formed by the ______ ______.
Formed by occipital bone
77
Posterior cranial fossa
Dorsum sellae forms:
anterior boundary and petrous and mastoid parts of temporals form anterolateral boundaries
78
Posterior cranial fossa
Clivus-
Clivus- marked incline from dorsum sellae to foramen magnum
79
Palatine bone: (2)
Foramina/Apertures
Greater palatine foramen
Lesser palatine foramen
80
Palatine bone: (2)
Nerves
Greater palatine nerve
Lesser palatine nerve
81
Palatine bone: (2)
Vessels
Descending palatine a. and v.
lesser palatine a.
82
Maxillae:
Foramina/Apertures
Incisive foramen
83
Maxillae:
Nerves
Nasopalatine nerve
84
Maxillae:
Vessels
Sphenopalatine a. and v.
85
Temporal bone: (2)
Foramina/Apertures
- External acoustic meatus
- Stylomastoid foramen
86
Temporal bone:
Nerves
Facial nerve (CN VII) exits
87
Temporal bone:
Vessels
Stylomastoid a.
88
Ethmoid bone (anterior cranial fossa):
Foramina/Apertures
Cribriform foramina
89
Ethmoid bone (anterior cranial fossa):
Nerves
Olfactory nerve (CN I)
90
Ethmoid bone (anterior cranial fossa):
Vessels
Anterior and posterior ethmoidal aa.
91
Sphenoid bone (middle cranial fossa):
Optic canal
Nerves:
Optic nerve (CN II)
92
Sphenoid bone (middle cranial fossa)
Optic canal
Vessels:
Ophthalmic a.
93
Sphenoid bone (middle cranial fossa)
Superior orbital fissure
Nerves: (4)
Oculomotor n. (CN III)
Trochlear n. (CN IV)
Ophthalmic n. (CN V1)
* Lacrimal n.
* Frontal n.
* Nasociliary n.
Abducent n. (CN VI)
94
Sphenoid bone (middle cranial fossa)
Superior orbital fissure
Vessels:
Superior ophthalmic v.
95
Sphenoid bone (middle cranial fossa)
Foramen rotundum
Nerves:
Maxillary branch of trigeminal n. (CN V2)
96
Sphenoid bone (middle cranial fossa)
Foramen ovale: (2)
Mandibular branch of trigeminal n. (CN V3)
Lesser petrosal n.
97
Sphenoid bone (middle cranial fossa)
Foramen spinosum
Nerves:
Middle meningeal branch of mandibular n. (CN V3)
98
Sphenoid bone (middle cranial fossa)
Foramen spinosum
Vessels:
Middle meningeal a.
99
Sphenoid bone (middle cranial fossa)
Foramen lacerum
(Located between the sphenoid, apex of
petrous temporal and basilar part of occipital)
Nerves: (2)
Deep petrosal nerve
Greater petrosal nerve
100
Sphenoid bone (middle cranial fossa)
Foramen lacerum
(Located between the sphenoid, apex of
petrous temporal and basilar part of occipital)
Vessels:
Meningeal arterial branches and small
vv.
101
Temporal bone
Carotid canal (middle cranial fossa)
Nerves:
Internal carotid sympathetic plexus
101
Temporal bone
Carotid canal (middle cranial fossa)
Nerves:
Internal carotid sympathetic plexus
102
Temporal bone
Carotid canal (middle cranial fossa)
Vessels:
Internal carotid a.
103
Temporal bone
Internal acoustic meatus
(posterior cranial fossa)
Nerves:
Facial n. (CN VII)
Vestibulocochlear n. (CN VIII)
104
Temporal:
Internal acoustic meatus
(posterior cranial fossa)
Vessels:
Labyrinthine a. and v.
105
Occipital bone (posterior cranial fossa)
Foramen magnum
Nerves: (2)
Medulla oblongata
Accessory n. (CN XI)
106
Occipital bone (posterior cranial fossa)
Foramen magnum
Vessels: (3)
Anterior and posterior spinal aa.
Vertebral aa.
Spinal v.
107
Occipital bone (posterior cranial fossa)
Jugular foramen
(Between occipital and petrous temporal)
Nerves: (3)
Glossopharyngeal n. (CN IX)
Vagus n. (CN X)
Accessory n. (CN XI)
108
Occipital bone (posterior cranial fossa)
Jugular foramen
(Between occipital and petrous temporal)
Vessels: (3)
Internal jugular v.
Inferior petrosal and sigmoid sinuses
Posterior meningeal a.
109
Occipital bone (posterior cranial fossa)
Hypoglossal canal
Nerves:
Hypoglossal n. (CN XII)
