Neuroanatomy Lab (Week 2)

Question 1

Dural reflections

Answer 1

Falx cerebri

Tentorium cerebelli (with tentorial notch)

Falx cerebelli

Question 2

Reabsorption of CSF into venous system

Answer 2

Arachnoid villi protruding into superior sagittal sinus

Large collections of arachnoid villi are called arachnoid granulations

Question 3

Cistern

Answer 3

Enlargement of subarachnoid space

Cisterna magna (cerebellomedullary cistern) between medulla oblongata and cerebellum

Interpeduncular cistern is hollow space at base of midbrain between cerebral peduncles

Superior/quadrigeminal cistern surrounds dorsal and lateral surface of midbrain

Question 4

Subarachnoid hemorrhage

Answer 4

In subarachnoid space, vessels (aneurysm or trauma) rupture to cause SAH

Branch points off circle of willis (85% anterior circulation, 15% posterior circulation)

Can cause excruciating headache and arterial spasm

Subarachnoid spaces: sulci, Sylvian fissure (lateral sulcus), basal cisterns (so can see blood in these spaces on MRI)

Question 5

Subdural hematoma

Answer 5

Result of head trauma with tearing of bridging veins on surface of cerebral cortex (note: veins in subdural space)

Slower venous bleeding

Shape is crescentic and can go all along outside of one hemisphere

Reflects with dural reflection

Deep to both layers of dura

Cannot cross midline

Can be along tentorium

Surgical evacuation often elective

Question 6

Epidural hematoma

Answer 6

Result of head trauma with lateral skull fracture and tearing of middle meningeal artery (which is in close contact with bone)

Shape is lens, lenticular, biconvex

Confined by dural insertions at sutures (coronal suture, lambdoid suture)

Superficial to both layers of dura, can cross midline

Surgical emergency or close observation

Question 7

Brain herniations

Answer 7

Space-occupying mass such as hematoma or tumor can compress train then cause it to be displaced into adjacent brain compartment (herniation)

Subfalcine or cingulate herniation: under falx

Central or diencephalic herniation: downward

Transtentorial or uncal herniation: displacing part of temporal lobe

Tonsillar herniation: forcing cerebellum into foramen magnum at base of skull (compress brainstem)