Intracranial Anatomy Flashcards
(42 cards)
1
Q
Neurocranium Components
A
Cranial vault and cranial base
2
Q
Cranial vault
A
- Calvaria or membranous neurocranium
- Develops from intramembranous ossification
3
Q
Cranial base
A
- Basicranium or chondral neurocranium
- Develops from endochondral ossification
4
Q
Viscerocranium
A
- Face and mandible
- Develops from branchial arches
5
Q
Types of bone in cranial vault
A
- Compact bone of inner and outer tables
- Diploë: spongy bone in the middle
6
Q
Cranial Sutures
A
- Fibrous joint: held together by Sharpey’s fibers (collagen type III)
- Sutural (Wormian) bones: small, irregular bones that develop within sutures
7
Q
Cranial vault sutures
A
- Coronal
- Lambdoid
- Metopic/frontal (fuses at 9 months)
- Pterion
- Sagittal
- Squamosal
8
Q
Facial (palatal) sutures
A
- Intermaxillary
- Transverse palatine
9
Q
Emissary veins
A
External veins that drain through diploic veins to internal dural sinuses. These are a potential route of infection from the scalp into the cranial vault.
10
Q
Cranial sinuses
A
- Frontal
- Ethmoidal
- Sphenoidal
- Maxillary (Antrum)
Also: mastoid air cells
11
Q
Semilunar hiatus
A
Drains frontal, maxillary, and anterior ethmoidal sinuses into nasal cavity
12
Q
Posterior ethmoidal and sphenoidal sinuses drain into…
A
nasopharynx
13
Q
Maxillary Sinus (Antrum)
A
- contains the CN V2, maxillary nerve (GSA to upper teeth, palate, nasal cavity)
- Maxillary dental roots can project into sinus
14
Q
Meninges from Superficial to Deep
A
- Dura mater
- Arachnoid mater
- Pia mater
15
Q
Arterial supply to meninges
A
middle meningeal artery from maxillary artery
16
Q
Innervation of meninges
A
- anterior and middle cranial fossae- CN V
- Posterior cranial fossa- CN IX, X C1-3
17
Q
Dura mater
A
- Endosteal layer (ends at foramen magnum)
- Meningeal layer (continues to spinal cord)
- Dural sinuses (venous drainage for intracranial region) form between layers
- Forms folds around parts of the brain (e.g. tentorium cerebelli, falx cerebri)
18
Q
- Dural folds
- Falx cerebri
- Tentorium cerebelli
A
- Formed by the meningeal layer of dura mater
- Falx cerebri separates the left and right cerebral hemispheres
- Tentorium cerebelli separates the cerebru, and cerebellum
19
Q
Arachnoid mater
A
Forms arachnoid granulations, which allow cerebrospinal fluid (CSF) to enter dural sinuses and return to systemic circulation
20
Q
Pia mater
A
- impermeable to fluid, encloses CSF around brain
- forms perivascular spaces that act as brain’s lymphatic system
21
Q
Meningeal Spaces Chart
A
22
Q
Dural Sinuses
A
- Venous drainage for the cranial cavity
- Returns CSF to circulation
- Lymphatic system runs along sinuses inside skull
23
Q
Dural Sinuses: Superior and Inferior sagittal sinuses
A
in falx cerebri
24
Q
Dural Sinuses: Straight sinus
A
at junction of falx cerebri and tentorium cerebelli
25
Dural Sinuses: transverse sinus
in tentorium cerebelli
26
Dural Sinuses: Sigmoid sinus
drain to internal jugular vein
27
Dural Sinuses: Cavernous sinus
surrounds internal carotid artery
28
Venous blood exits skull through:
* internal jugular vein (sigmoid sinus)
* vertebral veins (vertebral venous plexuses)
* Maxillary vein (cavernous sinus and pterygoid venous plexuses)
29
Cranial base: Foramen (pl. foramina)
holes where cranial nerves and vasculature enter/exit the skull
30
Cranial base: fossa (pl. fossae)
* depression in cranial base
* anterior cranial fossa: frontal lobes, olfactory bulbs
* middle cranial fossa: temporal lobes, pituitary gland
* posterior cranial fossa: cerebellum, medulla, pons
31
Middle Cranial Fossa Contents
* temporal lobe of brain
* pituitary gland
* internal carotid artery, opthalmic arteries
* middle meningeal vessels and nerves
* cavernous sinus
* cranial nerves: CN II, III, IV, V, VI
* trigeminal ganglion (CN V)
* autonomic nerves: greater (CN VII) and lesser (CN IX) petrosal nn.
32
Cavernous Sinus Contents (nerves/arteries)
* Internal carotid artery
* CN III- oculomotor n.
* CN IV- trochlear n.
* CN V1- opthalmic n.
* CN V2- maxillary n.
* CN VI- abudcent n.
33
Anastomosis
* an alternative route for vascular flow
* multiple pathways of getting blood to or from the source
* seen around joints, organs with high vascular requirements
34
Carotid arteries
* external carotid a.
* supplies face, scalp, skull, meninges
* internal carotid a.
* supplies brain, eyes
* carotid sinus and body at bifurcation of carotid aa.
* monitor blood chemistry and pressure
35
venous drainage of superficial face
1. facial vein
2. common facial vein
3. internal jugular vein
4. brachiocephalic vein
5. superior vena cava
36
Opthalmic veins
* connect cavernous sinus to facial veins
37
Cavernous sinus
* intracranial
* found in middle cranial fossa
* surrounds the internal carotid artery
38
Cavernous sinus drainage
1. Cavernous sinus
2. Sigmoid sinus
3. Internal jugular vein
4. right brachiocephalic vein
39
Anterograde flow
at rest, blood drains inferiorly from the facial v. to the internal jugular v.
40
retrograde flow
* intracranial hyperthermia (the brain gets hot!), blood drains posteriorly through the orbits (opthalmic vv.) to the cavernous sinus
* counter-surrent cooling
* venous blood in the cavernous sinus cools arterial blood in the internal carotid artery before brain
41
danger triangle
retrograde venous flow from skin in this region can spread skin infections into the cavernous sinus, meninges, and brain
42
Cranial nerves
I: Olfactory
II: Optic
III: Oculomotor
IV: Trochlear
V: Trigeminal
VI: Abducens
VII: Facial
VIII: Vestibulochoclear
IX: Glossopharyngeal
X: Vagus
XI: Spinal accessory
XII: Hypoglossal
