Week 1 - Dry Room

Question 1

From which arteries do the left and right vertebral arteries arise?

Answer 1

Subclavian Artery

Question 2

From which arteries do the left and right internal carotid arteries arise?

Answer 2

Common carotid artery

Question 3

How is the basilar artery formed and which part of the brainstem is it most closely related to?

Answer 3

Two vertebral arteries converge, uniting at the junction of the medulla and pons

Most closely related to medulla

Question 4

Which artery completes the anterior of the Circle of Willis by linking the anterior cerebral arteries?

Answer 4

Anterior communicating artery

Question 5

Which arteries complete the posterior of the circle of willis by linking the internal carotid arteries to the posterior cerebral arteries?

Answer 5

Posterior communicating artery

Question 6

In which fissure/ groove / sulcus of the brain does the anterior cerebral artery travel?

Answer 6

Median longitudinal fissure

Question 7

In which fissure/ groove / sulcus of the brain does the middle cerebral artery travel?

Answer 7

Lateral sulcus

Question 8

Which cerebral artery/arteries supply the primary motor cortex?

Answer 8

Anterior and middle cerebral artery

Question 9

Which cerebral artery/arteries supply the primary sensory area?

Answer 9

Anterior and middle cerebral artery

Question 10

Which cerebral artery/arteries supply the primary visual cortex?

Answer 10

Posterior cerebral artery

Question 11

Which cerebral artery/arteries supply the primary auditory area?

Answer 11

Middle cerebral artery

Question 12

Which cerebral artery/arteries supply the area for olfaction?

Answer 12

Posterior cerebral artery

Question 13

What parts of the brain do the vertebra-basilar system supply?

Answer 13

Brainstem
Cerebellum
Occipital lobe

Question 14

Which cerebral artery runs immediately superior to the superior cerebellar artery?

Answer 14

Posterior cerebral artery

Question 15

Which cranial nerve emerges from just above the superior cerebellar artery?

Answer 15

Trochlear IV

Question 16

Aneurysms of the posterior cerebral artery are common in a location where it causes palsy of the cranial nerve III emerging just below.
What are the clinical manifestation of palsy of this cranial nerve?

Answer 16

Unable to move affected eye properly

Eye adopts a resting “down and out” position

Question 17

Why is there nerve supply to the arteries supplying the brain?

Answer 17

Due to the importance of the brain, there is a good combination of sensory and motor nerves which help to control blood flow to the brain.

Question 18

What is the carotid sinus?

Answer 18

This is a dilatation located on the terminal part of the common carotid artery (or the proximal part of the internal carotid artery).
It is a pressure receptor which monitors the flow of blood to the head, including the brain.
Sensory nerves from the carotid sinus run in the glossopharyngeal nerve and the vagus nerve.

Question 19

What is the carotid body?

Answer 19

This is an area on the posterior wall of the terminal part of the common carotid artery in the neck.
It contains chemoreceptors which are sensitive to low oxygen levels (anoxia).
Sensory nerves from these receptors run in the glossopharyngeal nerve.
Detection of anoxia will stimulate increased heart rate, respiration and blood pressure

Question 20

What is the sympathetic motor supply to the brain?

Answer 20

Sympathetic motor nerves from the superior cervicle ganglion form a plexus around the internal carotid artery.
This plexus enters the skull, with the artery, through the carotid canal, and continues along the main branches of the internal carotid artery

Question 21

Explain the venous drainage of the brain

Answer 21

The brain is drained by a series of veins which drain into dural venous sinuses.
These sinuses are present between the periosteum and the cranial dura.

Cerebral veins are often divided into a superficial and deep group.
Among the deep group the Great cerebral vein (of Galen) can be seen on wet specimens and models

Question 22

Into which vein in the neck do the dural venous sinuses drain into?

Answer 22

Internal jugular vein

Question 23

Through which foramen in the skull does the internal jugular vein pass?

Answer 23

Jugular foramen

Question 24

In addition to the internal jugular vein there are other connections between the intracranial venous sinuses and the extra cranial venous network.
Since these are not major routes for blood drainage why do we need to know about them?

Answer 24

These are potential routes of infection which may be carried in the blood (e.g. following cut/ abrasion to the scalp/ face

Question 25

How do the veins in the brain and the cranial venous sinuses differ to veins outside the skull?

Answer 25

Do not have valves to prevent back flow of blood from outside the cranium back into the cranium

Question 26

Name the important connection between intracranial venous sinuses and extra cranial veins involving the superior ophthalmic vein

Answer 26

The superior ophthalmic vein drains into the cavernous sinus within the cranial cavity.
On the outside of the cranial cavity it is continuous with the facial vein.

Question 27

Name the important connection between intracranial venous sinuses and extra cranial veins involving the emissary veins

Answer 27

Emissary veins are small veins that connect the cranial venous sinuses with the dipole of the skull containing the blood sinuses in the bone marrow of the dipole which in turn are continuous with the veins in the superficial fascia overlying the outer part of the skull and scalp.

Question 28

Name the important connection between intracranial venous sinuses and extra cranial veins involving the inferior petrosal sinuses

Answer 28

The inferior petrosal sinuses lie at the base of the brain and are connected to each other (left and right) by the basilar sinus.
This small sinus also communicates inferiorly with the internal vertebral sinus

Question 29

Why do we need to know about the cavernous sinus?

Answer 29

This venous sinus deserves a special mention because of a number of neuromuscular structures which pass through it

Question 30

What veins drain into the cavernous sinus?

Answer 30

Middle cerebral vein
Superior and inferior ophthalmic veins
Sphenoparietal sinus

Question 31

What structures does the cavernous sinus closely relate to?

Answer 31

Nerves: Oculomotor (III), Trochlear (IV), Ophthalmic (V1), Maxillary (V2), Abducens (VI)

Internal carotid Artery
(ruptures = arteriovenous fistula (carotidcavernous fistula))

Sphenoid sinus

Pituitary gland (pituitary adenoma)

Connections with facial vein through superior ophthalmic vein (Infections from danger area of face)

Question 32

Explain cavernous sinus thrombosis

Answer 32

CST is a clinical condition due to spreading of infection from the nose, sinuses, ears or teeth.

Caused by a clot in the cavernous sinus usually due to infection

CST results in bulging eyes and loss of vision among other things. This is due to the failure of the superior and inferior ophthalmic veins to drain and also paralysis of the nerves coursing through it.

Emergency which is treated with antibiotics or sometimes drainage.

Question 33

What arteries supply the spinal cord?

Answer 33

3 longitudinally running spinal arteries (1 anterior and 2 posterior) and multiple segmental spinal arteries supply the spinal cord

Question 34

Branches from which arteries fuse to form the anterior spinal artery?

Answer 34

Vertebral arteries

Question 35

Which arteries are the posterior spinal arteries branches of?

Answer 35

Vertebral arteries

Question 36

Describe the venous drainage of the spinal cord

Answer 36

In general, the distribution of the veins of the spinal cord is similar to that of the spinal arteries.
The longitudinally oriented anterior and posterior spinal veins communicate freely with each other and join the internal vertebral (epidural) venous plexus lying in the epidural space.
This plexus of veins passes superiorly within the vertebral canal through the foramen magnum to communicate with the dural sinuses and veins within the skull.
The internal vertebral venous plexus also communicates with the external vertebral venous plexus on the external surface of the vertebrae.

Question 37

What fluid circulates in the subarachnoid space?

Answer 37

Cerebrospinal fluid

Question 38

Apart from CSF what other structures are present in the subarachnoid space?

Answer 38

Trabecculae

Numerous arteries and veins

Question 39

Which structures does the fall cerebri separate?

Answer 39

Cerebral hemispheres

Question 40

To what bony structures does the fall cerebra attach anteriorly?

Answer 40

Ethmoid and crista gali processes

Question 41

Which dural venous sinus runs within the upper border of the falx cerebri?

Answer 41

Inferior sagittal sinus

Question 42

Which dural venous sinus runs along the upper border of the falx cerebri?

Answer 42

Superior sagittal sinus

Question 43

Which structures does the tentorium cerebelli separate?

Answer 43

Cerebellum from cerebrum

Question 44

To what bony points does the anterior edge of the tentorium cerebelli attach to?

Answer 44

Superior angle of the petrous part of the temporal bone

Question 45

Which dural venous sinus runs along the attachment of the falx cerebri to the tentorium?

Answer 45

Superior Petrosal Sinus

Question 46

What is the dural fold that separates the two cerebellar hemispheres called?

Answer 46

Falx cerebelli

Question 47

What is the fold of dura that surrounds the pituitary stalk called?

Answer 47

Diaphragm Sellae

Question 48

What is the arterial supply of the dura mater?

Answer 48

Branches of numerous arteries including the Internal Carotid artery, branches of the External Carotid Artery and vertebral arteries

One of the clinically important meningeal arteries is the middle meningeal artery.
This is a specific branch of the maxillary artery that supplies the dura mater

Question 49

Through which foramen in the skull does the middle meningeal artery enter the cranial cavity?

Answer 49

Foramen spinosim

Question 50

What are the ventricles of the brain?

Answer 50

Ventricles are interconnected spaces/ cavities that lie within the brain.
The central canal of the spinal cord is a continuation of the ventricular system within that structure

Question 51

What embryological structures are the ventricles formed from?

Answer 51

Cavity of the neural tube

Question 52

What is the name given to the specialised structures lining the ventricles that generate CSF?

Answer 52

Choroid plexus

Question 53

Where do the parts of the lateral ventricle lie?

Answer 53

Anterior horn = frontal lobe
Body = Parietal lobe
Posterior horn = Occipital lobe
Inferior horn = Temporal lobe

Question 54

Where does the inter ventricular foramen (foramen of Monro) lie?

Answer 54

Between column of fornix and anterior pole of the thalamus

Just under corpus calosum

Question 55

Where does the third ventricle lie?

Answer 55

Bordered In between the thalamus and hypothalamus

Question 56

Where does the cerebral aqueduct (of the midbrain) lie?

Answer 56

Runs the length of the midbrain beneath inferior and superior colliculi

Question 57

Where does the 4th ventricle lie?

Answer 57

Dorsal surface of brainstem beneath cerebellum

Question 58

How does CSF pass into the subarachnoid space from the 4th ventricle?

Answer 58

Foramen of Magendie

Question 59

At which location is cerebrospinal fluid finally resorbed back into the general circulation

Answer 59

Arachnoid granulations of the dural venous sinuses

Question 60

Explain the clinical significance of CSF

Answer 60

If the circulation of CSF is restricted then there will be an increase in intracerebral pressure.
In infancy congenital defects in circulation lead to a progressive enlargement of the head and a reciprocal reduction in the cerebral matter.
This condition is known as hydrocephalus and can occur in isolation or as part of spina bifida.
This is a very treatable condition using a shunt to redirect the fluid out of the cerebral circulation into the deep venous system.

Question 61

How does hydrocephalus in adults vary compared to children?

Answer 61

In later life disruption of CSF circulation can also be associated with trauma and will not result in the enlargement of the head.
This is because adults do not have fontanelles so have no room to expand. Compression will result which can cause herniation of the brainstem (+ cerebellum) through the foramen magnum.