Skull and Cranial Cavity

Question 1

Scalp

Answer 1

Consists of 5 layers

Extends over neurocranium

Quite vascular

Question 2

Innervation of the scalp

Answer 2

Trigeminal nerve

Spinal cutaneous nerves

Question 3

Bones of the skull

Answer 3

Neurocranium and viscerocranium 22 bones

Sometimes extra bones

Question 4

Neurocranium bones

Answer 4

8

• occipital
• 2 temporal
• 2 parietal
• sphenoid
• ethmoid
• frontal

Question 5

Visceracranium bones

Answer 5

14

• 2 nasal conchae
• 2 nasal bones
• 2 maxilla
• 2 palentine bones
• 2 zygomatic bones
• 2 lacrimal bones
• vomer
• mandible

Question 6

Foramina of the skull function

Answer 6

Permits nerves and blood vessels to enter or leave the cranial cavity

Question 7

Divisions in base of skull

Answer 7

Cranial fossa

• Anterior
• Middle
• Posterior

Question 8

Meninges layers

Answer 8

Dura mater

Arachnoid mater

Pia mater

Question 9

Role of meninges

Answer 9

Protection

Support network for blood vessels

Forms a fluid filed cavity to cushion and nourish the brain

Brain has to float in CSF so it doesn’t crush nerves below it

Question 10

2 Dura mater layer

Answer 10

Endosteal layer

Meningeal layer

(closely applied to each other)

Dural sinus is split between containing venous structure

Question 11

SCALP

Answer 11

Skin

Connective tissue (dense)

Aponeurotic layer

Loose connective tissue

Pericranium

Question 12

Meningeal layer

Answer 12

Around brain and spinal cord

Question 13

Endosteal layer

Answer 13

Lines the skull

Doesn’t go down spinal cord

Question 14

Dura mater nerve supply

Answer 14

CN V (trigeminal)

CN X (vagus)

C1-3

Sympathetic

Question 15

Dura mater blood supply

Answer 15

Middle meningeal artery

- tiny artery winding throw foramen spinosum to inside of skull

Question 16

Meningeal layer of dura

Answer 16

Series of folds which divide the cranial cavity

Restrict movement of the brain

• flax cerebri
• tentorium cerebelli
• flax cerebelli

Question 17

Falx cerebri

Answer 17

Separates cerebral hemispheres

Question 18

Tentorium cerebelli

Answer 18

Separates cerebellar hemispheres from cerebral hemispheres

Question 19

Falx cerebelli

Answer 19

Separates cerebellar hemispheres

Question 20

Dura sensitive to stretching

Answer 20

Anatomical basis of headache

Question 21

Damage to middle meningeal artery

Answer 21

Extradural haematoma

Question 22

Tentorial herniation

Answer 22

Caused by space occupying lesion cause herniation of temporal lobe

e.g. tumour

Question 23

Arachnoid mater

Answer 23

Thin avascular between pia and dura

Loosely applied layer with projections

All structures passing to/ from brain pass through subarachnoid space

Question 24

Cerebrospinal fluid

Answer 24

Produced by choroid plexus in brain

Contained in subarachnoid space

Arachnoid granulations affect the transfer of CSF to the venous sinuses

Question 25

Role of CSF

Answer 25

Provides buoyancy to brain protecting it from mechanical forces

Question 26

Pia mater

Answer 26

Very delicate vascular membrane Closely invests brain following gyri/ sulci Cerebral arteries enter brain carrying sheath of pia mater with them

Question 27

Spinal cord meninges

Answer 27

Dura mater (only meningeal layer) Arachnoid mater Pia mater Form part of covering of spinal nerve roots

Question 28

Leptomeningitis

Answer 28

Infection and inflammation in the arachnoid and pia mater (leptomeninges) Infection may enter the subarachnoid space and enter the blood (septicaemia)

Question 29

Dural sinuses

Answer 29

Sit between dural fold Drained blood and CSF from brain via cerebral veins Communicate with the veins of the skull and scalp Thick walled endothelium (no valves or smooth) Drain into internal jugular vein

Question 30

Blood supply to the brain

Answer 30

Internal carotid artery and vertebral artery Branches anastomose to form circle of willis Inside skull there are two terminal branches (anterior and middle cerebral artery)

Question 31

Vertebral arteries

Answer 31

Pass within cervical passes within cervical vertebrae and enter foramen magnum where they unite to form basilar artery Come of subclavian arteries

Question 32

Circle of Willis

Answer 32

Formed by anastomses 2xICA 2xVertebral arteries

Question 33

Cerebral artery

Answer 33

Each has its own pattern of supply to brain

Question 34

Anterior cerebral artery supplies

Answer 34

Medial and superior surfaces and temporal pole

Question 35

Middle cerebral artery supplies

Answer 35

Lateral surfaces and temporal pole

Question 36

Posterior cerebral artery supplies

Answer 36

Inferior surfaces and occipital pole

Question 37

Stroke

Answer 37

Embolism in cerebral artery No anastomosis of cerebral arteries once inside brain

Question 38

Infant skulls

Answer 38

Lower part of fascial skeleton develops in response to eating actions

Question 39

Arachnoid granulations

Answer 39

Pops up into dural sinus Needed to get rid of CSF to venous sinus, eventually to jugular vein to be excreted

Question 40

Superior sagittal sinus

Answer 40

Sinus at the top of the brain

Question 41

Confluence of sinuses

Answer 41

Right in the middle of the brain Blood then goes down left or right

Question 42

Transverse sinus

Answer 42

Left and right Drains from confluence of sinuses

Question 43

Common carotid

Answer 43

Off arch of aorta Up neck and divides to external and internal External goes forward Internal goes straight to brain