Session 1: Cranium, Meninges and Brain

Question 1

What is another name for the facial skeleton?

Answer 1

Visceroskeleton

Question 2

What are the two parts of the cranium?

Answer 2

Vault and Base

Question 3

Name all the cranial bones.

Answer 3

Frontal, Parietal, Temporal, Occipital, Sphenoid, Ethmoid

Question 4

Name all the facial bones.

Answer 4

Mandible, Maxilla, Zygomatic, Nasal, Lacrimal, Inferior Nasal Concha, Vomer, Palatine

Question 5

What are the gaps between the bones in the skull during development called? Identify between which bones they are and when they close.

Answer 5

Fontanelles
anterior - frontal & parietal bones (18-24 months)
posterior - parietal & occipital bones (2-3 months)

Question 6

What is the role of conchae?

Answer 6

increase the surface area of the upper respiratory tract

Question 7

What are the tough fibrous joints between bones in the skull called?

Answer 7

Sutures

Question 8

Give an example of a synovial joint within the skull.

Answer 8

Temporo-mandibular Joint

Question 9

Give the names of the sutures between a) frontal and parietal bones, b) parietal bones and c) parietal and occipital bone.

Answer 9

Coronal Suture
Sagittal Suture
Lambdoid Suture

Question 10

What is the name given to the point at which the sagittal suture meets the coronal suture?

Answer 10

Bregma

Question 11

What is the name given to the point at which the sagittal suture meets the lambdoid suture?

Answer 11

Lambda

Question 12

List the three folds of dura mater in the cranium

Answer 12

Falx cerebri - along the fissure between the two cerebral hemispheres
Falx cerebelli - separates the two cerebellar hemispheres
Tentorium cerebelli - between cerebellum & occipital lobes

Question 13

How can the cranial base be divided? Name the relations to the brain regions and skull bones

Answer 13

Cranial Fossae:
Anterior - frontal lobes (frontal, ethmoid + sphenoid bones)
Middle - temporal lobes ( temporal + sphenoid bones)
Posterior - cerebellum (temporal + occipital bones)

Question 14

Which layer of the meninges goes in and out of the sulci?

Answer 14

Pia Mater

Question 15

What are the two layers of dura in the cranium?

Answer 15

Periosteal and Meningeal

Question 16

What difference between the cranial dura and spinal dura allows for an epidural space?

Answer 16

At the foramen magnum the dura goes from having two layers (periosteal and meningeal) to just one layer (equivalent of the meningeal layer).
This means that there is an epidural space.

Question 17

What drains into the venous blood filled spaces between dural layers?

Answer 17

CSF via the arachnoid villi

Question 18

Describe the arrangement of dural venous sinuses and the direction of blood flow

Answer 18

superior sagittal sinus - along the top of falx cerebri
inferior sagittal sinus - along bottom of falx cerebri
inf sagittal + great cerebral vein of Galen = straight sinus
straight sinus + sup sagittal + occipital sinus = confluence
Confluence drain through R & L transverse sinuses into to R & L sigmoid sinus (which forms R & L internal jugular veins)
inf & sup petrosal sinuses (R&L) drain into sigmoid/transverse from cavernous sinuses (R&L)
Cavernous sinuses drain from R&L pterygoid plexi, sup & inf ophthalmic veins
Ant & post intracavernous sinuses connect R&L cavernous sinuses

Question 19

What flat sheet of dura (with a small hole in it) keeps the pituitary gland in the sella turcica?

Answer 19

Diaphragma sellae

Question 20

List three different types of brain herniation and their consequences.

Answer 20

Subfalcine – cingulate gurus (of frontal lobe) goes under falx cerebri
Uncal/transtentorial/uncinate – inner part of temporal lobe (uncus) goes under tentorium cerebelli – which affects the midbrain and can cause pupil/vision problems & unconsciousness
Tonsilar – cerebellar tonsils go through foramen magnum – can affect medulla and cause cardiorespiratory failure

Question 21

Which two main vessels supply the circle of Willis?

Answer 21

Vertebral arteries and internal carotid arteries

Question 22

There is a weak point in the skull behind which you find the largest artery entering the skull. Name the part of the skull in question and the artery. Explain the clinical significance of this

Answer 22

Pterion – frontal + parietal + sphenoid + temporal bones meet here
Middle meningeal artery
Trauma to pterion = ruptured MMA = extradural haemorrhage

Question 23

What are emissary veins and what is their clinical relevance?

Answer 23

Drain blood from scalp (outside of skull) into superior sagittal sinus via parietal foramina

Provide an entry route for infections to enter intracranial space

Question 24

Which veins drain into the cavernous sinus?

Answer 24

Superior and inferior ophthalmic veins

There is also communication with the pterygoid plexus

Question 25

Which vein is joined to the end of the straight sinus at the pointwhere the inferior sagittal sinus joins the straight sinus?

Answer 25

Great cerebral vein

Question 26

What is the pterygoid plexus?

Answer 26

A venous plexus of considerable size that is situated between the temporalis muscle and lateral pterygoid muscle, and partly between the two pterygoid muscles

Question 27

In between which meningeal layers do you find venous sinuses? Also where do you find diploic veins

Answer 27

Diploic veins are found between inner and outer parts of compact bone of the skull (within the skull bone) and drain into venous sinuses Venous sinuses are found between periosteal and meningeal layers of dura mater

Question 28

Name three structures found within the cavernous sinus.

Answer 28

Internal carotid artery Various cranial nerves (occulomotor, trochlear, trigeminal (ophthalmic and maxillary divisions) and abducens) Pituitary Gland

Question 29

What are the different tissue layers of the scalp? | What is the clinical importance of a laceration there?

Answer 29

``` Skin Connective Tissue Aponeurosis Loose Areolar Tissue Periosteum ``` Laceration to the heavily perfused scalp (by ext. carotid + ophthalmic branches) will lead to profuse haemorrhage due to the dense connective tissue keeping the cut vessels open

Question 30

What is the tentorial notch and what is its clinical significance?

Answer 30

triangular opening in the tentorium cerebelli through which the brainstem extends downwards Increased intracranial pressure = part of the temporal lobe pushed through this opening

Question 31

Which major arteries pass through the foramen magnum?

Answer 31

Vertebral arteries

Question 32

List all the cranial nerves and the foramine through which they pass

Answer 32

Olfactory (I) – Cribiform Plate Optic (II) – Optic Canal Oculomotor (III), Trochlear (IV), Trigeminal (ophthalmic – V1 (V)) and Abducens (VI) – Superior Orbital Fissure Facial (VII) and Vestibulocochlear (VIII) – Internal Acoustic Meatus Glossopharyngeal (IX), Vagus (X) and Accessory (XI) – Jugular Foramen Hypoglossal (XII) – Hypoglossal Canal

Question 33

List the three branches of the trigeminal nerve and the foramina through which they pass

Answer 33

Ophthalmic – Superior Orbital Fissure Maxillary – Foramen Rotundum Mandibular – Foramen Ovale

Question 34

Which vessel passes through the optic canal?

Answer 34

Ophthalmic Artery

Question 35

Which vessel passes through the superior orbital fissure?

Answer 35

Superior Ophthalmic Vein and Inferior Ophthalmic Vein

Question 36

Which foramen does the middle meningeal artery and vein pass through?

Answer 36

Foramen Spinosum

Question 37

Which foramen does the internal carotid artery pass through?

Answer 37

Carotid Canal

Question 38

Which vessel passes through the internal acoustic meatus?

Answer 38

Labyrinthine Artery

Question 39

Which vessel passes through the jugular foramen?

Answer 39

Sigmoid Sinus --> Internal Jugular Vein

Question 40

Which foramen do the spinal roots of the accessory nerve pass through?

Answer 40

Foramen Magnum

Question 41

Name another vein that can provide entry for infections from the outside into the cranium

Answer 41

Facial vein connects with the cavernous sinus