sievert cranial cavity

Question 1

two divisions of the skull

Answer 1

neurocranium (bones around brain)

viscerocranium (facebones)

Question 2

neurocranium formation

Answer 2

large flatbones, most formed INTRAmembranously…

PARAXIAL MESODERM (somites)

Question 3

laryngeal bones come from what embryo origin?

Answer 3

lateral plate mesoderm

Question 4

prechordal plate

Answer 4

The division between neural crest derived and paraxial derived occurs at the ROSTRAL end of the notochord

Question 5

why do you tend to see heart tube defects accompanied w/ skull defects?

Answer 5

the mesenchyme that is neural crest in origin that makes the face is form the same block that makes the heart!!!!

Question 6

embryo derivative of the viscerocranium?

Answer 6

neural crest and ectoderm

Question 7

sphenoid bone embryo

Answer 7

everything anterior to the body =ectoderm and neural crest

everything posterior to that = paraxial mesoderm

Question 8

most of the bone develops by what kinda bone formation?

Answer 8

membranous!

Question 9

what parts of the neurocranium are referred to the as the chondrochranium coz they do endochondrial ossification?

Answer 9

most of sphenoid, the ethmoid, and part of the temporal and occipital bones

Question 10

viscerocranium bone dev

Answer 10

• membranous
• neural crest

cartilagenous exceptions: middle ear ossicles, laryngeal cartilages, and hyoid bone

Question 11

why are craniofacial defects so common?

Answer 11

coz lots of the skull comes form neural crest

Question 12

why is newborn face so small?

Answer 12

small jaw, no teeth, and no paranasal sinuses… and underdeveloped facial bones

Question 13

craniostynosis vs cranioschisis

Answer 13

stynosis = premature suture closure
schisis= incomplete closure of neural pore (amniotic fluid eats up brain tissue and relts in anencephaly)

Question 14

cranioschisis results in

Answer 14

ancephaly

additionally can also get:
cranial meningoencephalocele (meninges bulging out w/ brain tissue out too) and cranial meningocele (just meninges bulging out)

Question 15

is there an epidural space in c-cavity?

Answer 15

nope! coz dura is tightly fused to cranial bones

Question 16

meningeal arteries location

Answer 16

maxillary artery —> middle meningeal traveling through foramen spinosum —-> travel between dura and cranium

note they are not embedded within the dura… though they erode the skull bone and the dura

Question 17

what forms the periosteum of the int. cranial cavity?

Answer 17

dura mater

Question 18

two layers of the dura

Answer 18

periosteal and meningeal, but they’re fused together all the way down to the foramen magnum

exception: dural sinus and dural reflections

Question 19

why is one meningeal artery more important?

Answer 19

middle meningeal is most important coz the anteiror and posterior meningeal arteries go to areas where bone is really thick

Question 20

epidural hematoma etiology and include hallmark

Answer 20

etio: forms between dura and the bone.. a high pressure bleed can disect the dura from the bone, causing an artificial space where the blood can chill and create pressure in
- increase in pressure will mess up respiratory and cardiovascular centers down by the foramen magnum
- hallmark: lucid interval

Question 21

arachnoid appearance

and subarachnoid vessel basics

Answer 21

lightish, clearish membrane that has CSF underneath it.

there are vessels (veins) in the subarachnoid… they can pierce the arachnoid, and then pierce the dura to enter dural sinuses

Question 22

location of pia on brain?

Answer 22

directly on surface of all sucli and gyra

Question 23

why are high speed changes bad for the brain?

Answer 23

you can shear off the veins that enter the dural sinuses from the subarachnoid space, causing a SUBDURAL hematoma

Question 24

fxn of arachnoid granulaitons

Answer 24

• they’re modified from arachnoid…
• fxn: one way valvs that pierce into dural venous sinuses and allow CSF to percolate in, giving the brain buoyancy and adding nutrients and stuff

Question 25

emissary vein pathological fxn

Answer 25

connects scalpt to dural venous sinus
patho: infection form outside can come into the dural sinus… especially bad coz the loose areolar tissue is prone to infections

Question 26

two types of subdural hematomas

Answer 26

acute (traumatic brain injury, rapid blood flow, poor outcome, surgery a must)

chronic (long and low, usually observation and drainage will cure, and good outcomes)

Question 27

the big dural reflexions to know fasho

Answer 27

falx cerebri
tentorium cerebelli
falx cerebelli