Neuro

Question 1

Sort the arterial branches of the Vertebro-Basilar system into:

o Those arising from the Vertebral Arteries

o Those arising from the Basilar Artery:

Answer 1

VA-
Pontine arteries
The labyrinthine (internal auditory/acoustic) artery
The anterior inferior cerebellar artery
The superior cerebellar artery
The posterior cerebral artery
BA-
The anterior spinal artery
The posterior spinal arteries
The posterior inferior cerebellar arteries

Question 2

State which territory each vessel supplies
o Vertebral
o Basilar

Answer 2

V -
upper spinal cord, medulla, inferior cerebellum including the floccular nodular lobe.
B -
Pons, most of the cerebellum, midbrain, posterior cerebreal cortex and inferior temporal lobe.

Question 3

Use knowledge of brain areas, supply to split into anerior circulation, posterior circulation or both
Ataxia

Answer 3

Cerebellar ataxia can arise from a posterior circulation stroke. The stroke will affect the vertebral or basilar arteries. The Superior cerebellar arteries and the anterior inferior cerebellar arteries stem from the basilar artery, and the posterior inferior cerebellar arteries originate from the vertebral arteries.

Question 4

CONT - Hemianopia

Answer 4

An Hemianopia would occur from a stroke affecting the visual pathways from the optic chiasm onwards to the occipital lobe. The most likely type would be a homonymous hemianopia which would occur from an occlusion of the Posterior cerebral artery, therefore a posterior circulation stroke would be more likely.

Question 5

CONT - Motor weakness

Answer 5

Motor weakness can occur from any stroke that affects the motor cortex or motor tracts of the brain and spinal cord. The anterior and middle cerebral arteries supply the primary motor cortex, this means that strokes of the anterior circulation will produce motor weakness. However, as the corticospinal tracts have to through the brainstem and spinal cord, a stroke affecting the brainstem could also produce weakness, therefore as the basilar arteries supply the brainstem a posterior circulation stroke could also produce motor weakness

Question 6

CONT - Unable to form words

Answer 6

Expressive aphasia will occur from a stroke of the artery supplying Brocca’s area in the frontal lobe of the brain. In right handed people Brocca’s area is almost always on the left so is supplied by the Left middle cerebral artery, so it is an anterior circulation stroke. In left handed people Brocca’s area is on the right in about 60% and left in 40%.

Question 7

CONT -Unable to understand speech

Answer 7

Receptive aphasia occurs in strokes involving Wernicke’s area, which is also supplied by the middle cerebral artery, so this is also in the anterior circulation

Question 8

CONT - Cranial nerve involvement

Answer 8

Cranial nerve involvement will occur in strokes affecting the midbrain, pons and medulla, which are supplied by the posterior circulation.

Question 9

CONT - Sensory loss

Answer 9

Sensory loss can occur from any stroke that affects the sensory cortex or sensory tracts of the brain and spinal cord. The anterior and middle cerebral arteries supply the sensory cortex, this means that strokes of the anterior circulation will produce sensory loss. However, as the sensory tracts have to travel through the brainstem and spinal cord, a stroke affecting the brainstem could also produce sensory loss, as the basilar arteries supply the brainstem a posterior circulation stroke could also produce sensory loss

Question 10

What structure produces CSF and where in the brain is it located. What path does CSF take from where it is formed to where it is reabsorbed?

Answer 10

CSF is produced by the choroid plexus the majority of the choroid plexus is located on the walls of the lateral ventricles along the choroid fissure. Choroid plexus is also present in the roofs of the third and fourth ventricles.
The CSF travels from the lateral ventricles through the foramen of Munro to the third ventricle. The fluid then flows through the aqueduct of Sylvius (cerebral aqueduct) into the fourth ventricle where it drains out of the foramen of Lushka and Magendie into the subarachnoid space.

Question 11

How is CSF reabsorbed?

Answer 11

CSF is reabsorbed by the arachnoid villi located in the dural venous sinuses. Aggregations of arachnoid villi are known as arachnoid granulations.

Question 12

From external to internal, correct order of the meningeal layers:

Answer 12

Dura, Arachnoid, Pia.