Cranial Cavity

Question 1

what are the 3 layers of mater surrounding the brain and where do they sit

Answer 1

dura - closest to skull
arachnoid - close to dura
pia - closest to brain

Question 2

what vessel supplies the meninges

Answer 2

middle meningeal artery - anterior and posterior branches

Question 3

describe the bone of the skull

Answer 3

outer and inner cortical tables

with spongy traberculae bone inside - diploy bone

Question 4

what is the falx cerebri

Answer 4

folding of dura mater, that separates the two hemispheres and protects the brain from movement. runs from crista galli anteriorly

Question 5

what is the superior sagittal sinus and what drains into here

Answer 5

large venous sinus that runs in the falx cerebri. superior cerebral vein drains into here

Question 6

what is arachnoid villi and why is it important

Answer 6

it drains CSF from subarachnoid space into superior sagittal sinus, to keep a balance. can become granulated

Question 7

what is paget’s disease

Answer 7

an issue with bone remodelling results in an increase mass of bone

Question 8

when might an extra dural haemhorrage occur and what vessel is involved

Answer 8

fracture of the bone or trauma to the pterion - ruptures middle meningeal artery. patient may lose consciousness in a few hours after accident

Question 9

when might a subdural haemhorrage occur and what vessels are involved

Answer 9

in elderly people, veins draining into superior sagittal sinus - cerebral veins - are teared after minor accident. can take weeks or months before patient loses consciousness

Question 10

when might a subarachnoid haemorrhage occur and what vessels are involved

Answer 10

pathological swelling at circle of willis - aneurysm. can happen at any age more common in mid life. patient loses consciousness immediately or after a severe headache. cerebral arteries involved

Question 11

what vessel might become blocked, resulting in signs of a stroke

Answer 11

middle cerebral artery. provides supply to motor speech area, face and upper limb. speech becomes slurred, face paralysed and upper limb paralysed. however, lower limb spared as this is supplied by anterior cerebral artery.

Question 12

what vessels drain into the straight sinus, and where does this meet the sagittal sinus

Answer 12

great cerebral veins drain the deep structures of brain. drains into straight sinus, which meets the sagittal sinus at the confluence of sinuses

Question 13

what follows after the sagittal sinus and straight sinus

Answer 13

sagittal sinus - right transverse sinus - right sigmoid sinus - through jugular foramen - right jugular vein
straight sinus - left transverse sinus - left sigmoid sinus - through jugular foramen - left jugular vein

Question 14

what is the cycle of CSF

Answer 14

produced in ventricles, exits into subarachnoid space via the 4th ventricle - arachnoid villi then project into superior sagittal sinus where it is resorbed as more is made

Question 15

what is the connection between cavernous sinus and blood clot? and what is the effect of this

Answer 15

can have infection in face, then travels in facial vein to cavernous sinus. the blood flow here is much slower, allowing bacteria to multiply. this can cause the blood to clot, meaning blood from the orbit cannot drain - swollen eye. also result in fever and infection

Question 16

what artery comes through the foramen spinosum

Answer 16

middle meningeal artery

Question 17

what bone forms the choncha

Answer 17

superior and middle - ethmoid

inferior concha is its own bone

Question 18

what type of epithelium lines the concha

Answer 18

respiratory epithelium - pseudostratified columnar with cilia and goblet cells

Question 19

what are the depressions around the concha called

Answer 19

meatus - after the concha they lie under, area above superior concha - sphenoethmoidal recess

Question 20

where do the frontal and maxillary sinus drain into

Answer 20

hiatus semilunaris - recess in middle meatus

Question 21

what is the role of the respiratory mucosa

Answer 21

warm the incoming air - trap any bacteria or micororganisms to prevent them reaching lower respiratory tract

Question 22

what lies at the ethmoidal bulia

Answer 22

ethmoidal sinus - small air sacs

Question 23

where does the nasolacrimal duct drain into

Answer 23

inferior meatus

Question 24

why are infections in the frontal sinus commonly linked with infection in maxillary sinus

Answer 24

drains into the same area - hiatus semilunaris

Question 25

why is it common to get infection in maxillary sinus

Answer 25

opening of maxillary sinus is at the top, therefore difficult to drain and if bacteria gets in, hard to get out - unless lying on side could come out

Question 26

describe the course of the maxillary nerve

Answer 26

exits skull through foramen rotundum - enters ptergopalatal fossa, gives branches to pterygopalatine ganglion, continues along the roof of maxillary sinus, gives greater and lesser palatine nerves and nasopalatine nerve, enters orbit through inferior orbital fissure where it becomes the infraorbital nerve - gives anterior and middle superior alveolar nerves, then passes through the infraorbital foramen to give branches supplying the face - palpebral and orbital branches

Question 27

how do malignancies in the maxillary sinus present

Answer 27

its a squamous cell carcinoma - metaplasia - in 2 ways
if at the top - affecting infraorbital nerve - pain in face
if at bottom - extends through palate and into oral cavity

Question 28

what is it called when an extraction of a molar forms a passage through to sinus

Answer 28

oro-antral communication