Anatomy Lab- Cranial Cavity

Question 1

what are dural infoldings/reflections?

Answer 1

Periosteal and meningeal layer of dura reflect away from each other to form dural infoldings: they divide the cranial cavity into compartments- forming partial partitions

Question 2

name the dural infoldings

Answer 2

Falx Cerebri
Tentorium Cerebelli
Falx cerebelli
Diaphragma sellae

Question 3

what does falx cerebri descend

Answer 3

descends vertically in the longitudinal fissure between the cerebral hemisphere

Question 4

what are the anterior and posterior attachment of falx cerebri

Answer 4

• Attaches anteriorly to the crista galli (projection of the ethmoid bone)
• Attaches posteriorly to the internal occipital protuberance

Question 5

what are dural venous sinuses

Answer 5

venous channels found in the dural infoldings/reflections

Question 6

what are the venous sinuses found in falx cerebri and tentorium cerebelli and where are they located

Answer 6

1. Superior sagittal sinus- found in the superior margin of the falx cerebri – small veins called cerebral veins drain into this sinus. Drains blood from lateral aspect of cerebral hemisphere
2. Inferior sagittal sinus- found in the inferior margin of the falx cererbri, Drains blood from medial aspect of cerebral hemisphere
3. Straight sinus- At the junction of the falx cerebri and tentorium cerebelli is the straight sinus into which the inferior sagittal sinus drains

Question 7

what does tentorium cerebelli divide

Answer 7

separates the cerebellum from the occipital lobe

Question 8

superior sagittal sinus and straight sinus meet at the ___________

Answer 8

confluence of sinuses

Question 9

describe the path of posterior drainage of the sinuses

Answer 9

• Transverse sinus (R and L) – runs laterally on both sides in the groove in the inferior surface of the occipital bone
• Drains into the sigmoid sinus (R and L) travels and drains into internal jugular veins through the jugular foramen

Question 10

describe the path of anterior drainage of the sinuses

Answer 10

• Ophthalmic veins drain into cavernous sinus
• sphenoidal emissary vein drains into cavernous sinus
• Cavernous sinus drains via inferior and superior petrosal sinus into sigmoidal sinus (R and L)
  o Sigmoid (R and L) sinus drains into internal jugular vein through the jugular foramen

Question 11

what is the floor of the cranial cavity divided into

Answer 11

The floor of the cranial cavity is divided into three distinct depressions. They are known as the anterior cranial fossa, middle cranial fossa and posterior cranial fossa.

Question 12

which skull bone is foramen rotundum and internal acoustic meatus located in

Answer 12

Foramen rotundum- sphenoid bone

internal acoustic meatus- temporal bone

Question 13

what structures pass through the foramen magnum in base of skull

Answer 13

medulla oblongata of brainstem
vertebral arteries
spinal arteries
tectorial membranes
alar ligament 
accessory nerve (CN XI)

Question 14

blood supply of visual cortex

Answer 14

calcarine branch of the posterior cerebral artery.