Skull and cranial cavity

Question 1

The scalp consists of how many layers?

Answer 1

5 layers

Question 2

The scalp extends over which structures?

Answer 2

Scalp extends over the neurocranium

Question 3

Innervation to the scalp is from which nerves?

Answer 3

Innervation to the scalp is from the trigeminal nerve and spinal cutaneous nerves

Question 4

The skull is comprised of how many bones?

Answer 4

22 bones

Question 5

What are neurocranium bones?

Answer 5

Bones of the cranium

Question 6

What are the viscerocranium bones?

Answer 6

Faial bones

Question 7

How many neurocranium bones are there?

Answer 7

8

Question 8

What are the 8 neurocranium bones?

Answer 8

• Occipital
• Two temporal
• Two parietal
• Sphenoid
• Ethmoid
• Frontal

Question 9

How many viscerocranium bones are there?

Answer 9

14 bones

Question 10

What are the 14 bones of the viscerocranium?

Answer 10

• Two nasal conchae
• Two nasal bones
• Two maxilla
• Two palatine bones
• Two zygomatic bones
• Two lacrimal bones
• Vomer
• Mandible

Question 11

What is the purpose of the foramina?

Answer 11

Foramina exist to permit nerves and blood vessels to enter or leave the cranial cavity

Question 12

What is the base of the skull divided into?

Answer 12

The base of the skull is divided into the anterior, middle and posterior cranial fossa

Question 13

Give examples of Foramina?

Answer 13

• Cribiform plate
• Optic canal
• Superior orbital fissure
• Foramen rotundum
• Foramen ovale
• Foramen spinosum
• Internal acoustic meatus
• Stylomastoid foramen
• Foramen lacerum
• Jugular Foramen
• Hypoglossal canal
• Foramen magnum

Question 14

What are the meninges?

Answer 14

The meninges are the connective tissue coverings of the brain and spinal cord. The outermost layer is the dura mater, a dense and tough tissue that is reduplicated to form the periosteum of the inner skull.

Question 15

What are the 3 layers of the meninges?

Answer 15

• Dura mater
• Arachnoid mater
• Pia mater

Question 16

What are the roles of the meninges?

Answer 16

• Protection
• Support network for blood vessels
• Form a fluid filled cavity to cushion and nourish the brain

Question 17

What are the two layers of the Dura mater around the brain?

Answer 17

• Endosteal layer

- Meningeal layer

Question 18

The meningeal layer of the dura mater lines which structures?

Answer 18

Around brain and spinal cord

Question 19

The endosteal layer of the dura mater lines which structure?

Answer 19

Just lines skull

Question 20

The dura mater is supplied by which nerves?

Answer 20

CN V, X, C1-3 and sympathetic

Question 21

What is the blood supply to the dura mater?

Answer 21

Middle meningeal artery

Question 22

Why is the meningeal layer of the dura arranged in a series of folds/septa which divides the cranial cavity?

Answer 22

Folds or reflections prevent/restrict movement of the brain.

Question 23

What is the falx cerebri?

Answer 23

Separates cerebral hemispheres

Question 24

What is the tentorium cerebelli?

Answer 24

Separates cerebellar hemispheres from cerebral hemispheres

Question 25

What is falx cerebelli?

Answer 25

Separates cerebellar hemispheres

Question 26

What is the anatomical basis of a headache?

Answer 26

Dura sensitive to stretching

Question 27

Damage to the middle meningeal artery leads to what?

Answer 27

Extradural (epidural) haematoma

Question 28

What is tectorial herniation caused by?

Answer 28

Caused by space occupying lesion cause herniation of temporal lobe

Question 29

Where is the arachnoid mater located?

Answer 29

Thin avascular layer between Pia and dura

Question 30

All structures passing to/ from brain pass through which structure?

Answer 30

Subarachnoid space

Question 31

Which structure contains cerebrospinal fluid?

Answer 31

Subarachnoid space (real space)

Question 32

What is is cerebrospinal fluid produced by?

Answer 32

Choroid plexus in brain ventricles. - It provides buoyancy to brain protecting it from mechanical forces e.g. blow to skull - Arachnoid granulations affect the transfer of CSF to the venous sinuses

Question 33

What is the Pia mater?

Answer 33

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

Question 34

Which structures form part of the covering of spinal nerve roots?

Answer 34

Spinal cord meninges (3 layers)

Question 35

What is Leptomeningitis?

Answer 35

- An infection and inflammation in the arachnoid and Pia mater (the leptomeninges). - The infection may enter the subarachnoid space and enter into the blood (septicaemia)

Question 36

Where does the dural sinus sit?

Answer 36

Sits between the dural folds

Question 37

Where does the dural sinus drain into?

Answer 37

Drain into internal jugular vein

Question 38

Dural Sinuses

Answer 38

- Sinuses sit between the dural fold Drained blood and CSF from the brain via cerebral veins - Communicate with the veins of the skull and scalp - Thick walled endothelium no valves or smooth muscle - Drain into jugular vein

Question 39

Which two main arteries supply the brain?

Answer 39

- internal carotid artery and vertebral artery

Question 40

The branches of the internal carotid artery and the vertebral artery anastomose to form what?

Answer 40

The circle of willis

Question 41

Inside the skull there are two terminal branches:

Answer 41

The anterior cerebral and middle cerebral artery

Question 42

Vertebral arteries passes within cervical vertebrae and enter foramen magnum where they unite to form the......

Answer 42

basilar artery

Question 43

What is the circle of willis formed by?

Answer 43

- Formed by anastomoses - 2 x ICA - 2 x vertebral arteries

Question 44

Draw the circle of willis

Answer 44

Refer to diagram

Question 45

Cerebral artery

Answer 45

- Each cerebral artery has its own pattern of supply to the brain - The anterior cerebral supplying the medial and superior surfaces of the brain and frontal pole - The middle cerebral supplying the lateral surfaces and temporal pole - The posterior cerebral supplying the inferior surfaces and occipital pole

Question 46

What is a stroke caused by?

Answer 46

- Caused by an embolism in a cerebral artery, no anastomosis of cerebral arteries once inside brain hence neurological deficit - Pressure from ICA and vertebral artery is same, no mixing in posterior communicating artery unless if ICA or vertebral artery occluded - blood passes back / forth across PCA to compensate for reduced blood flow

Question 47

The layer of the meninges that is avascular and loosely applied is the:

Answer 47

The arachnoid layer