Scalp And Cranial Caivty

Question 1

What are the boundaries of the scalp

Answer 1

From the superior nuchal line of the occipital bone to the supraorbital margins of the frontal bone

Question 2

What are the 5 layers of the SCALP

Answer 2

S - Skin ; outermost layer
C - (dense) Connective tissue
A - Epicranial Aponeurosis
L- Loose connective tissue
P - Pericranium

Question 3

Which three layers make up scalp proper?

Answer 3

Skin, Dense connective tissue and Aponeurosis

Question 4

Where is skin on the scalp the thickest

Answer 4

Over the occipital bone

Question 5

Which layer of scalp proper is richly vascularised and contains cutaneous nerves

Answer 5

Dense connective tissue - An injury to scalp and it will bleed profusely

Question 6

What is the epicranial aponeurosis - what does it prevent

Answer 6

Tendon and muscle layer of occipitofrontalis

This layer prevents superficial wounds from gaping open, if this area is compromised sutures are required

Question 7

What is the function of the two bellies of the occiptofrontalis

Answer 7

The frontal belly functions to wrinkle the forehead while the occipital belly functions to then smooth it back out.

These muscle bellies create tension between each other and an injury here will cause a lot of gaping

Question 8

What is the purpose of the loose layer of connective tissue in the scalp

Answer 8

This area allows for movement of the outer layers of the scalp;

This area contains spaces ( spongy bone)susceptible to distension or infection spread

Question 9

What is the pericranium

Answer 9

It is the external periosteum of the skull, it is firmly attached

Question 10

Between the Aponeurosis and the pericranium there are poteintal spaces for accumulation of fluid( e.g. blood) or spread of infection.

This fluid or infection can spread to the eyelids or the root of the nose, why?

Answer 10

This is because the frontal belly of the occipitofrotnalis inserts into skin and subcutaneous tissue and NOT BONE.
- this means that there is no bony attachment to stop the infection from spreading so it continues to plead to eyes and root of nose

Question 11

Why can the brain be at risk in an infection of the loose connective tisssue

Answer 11

This is due to the emissary veins which can spread the infection to the brain causing things such as meningitis

Question 12

What is the arterial supply of the scalp

Answer 12

Internal and external carotid arteries supply the scalp

Internal ( anteior scalp) - supraorbital and supratrochlear branches

External (posterior scalp) ) - superficial temporal, posterior auricular and occipital branches

Question 13

Why does the scalp tend to bleed profusely when lacerated and why is this bleeding difficult to stop

Answer 13

This is due to the presence of many arterial anastomoses which lie superficially hence leading to profuse bleeding when lacerated

The connective issue layer is dense and therefore the anrites cannot constrict as much making it difficult to stop the bleeding

Question 14

The veins of the scalp run along with the arteries of the scalp and have the same names.

Where do the veins drain into and which one is the exception

Answer 14

They all drain into the external jugular vein with the one exception of the occipital vein which drains into the internal jugular vein

Question 15

The lymphatic drainage of the scalp is via 2 means, what are these

Answer 15

Anterior ; Pre-auricular and parotid nodes

Posterior; mastoid and occipital nodes and these drain into the deep cervical nodes

Question 16

Cribriform plate fractures can present with what and note three symptoms

Answer 16

CSF rhinorrhoea

-metallic taste at back of throat
- headache that worsens when you sit up improves when you lie down
- watery discharge from nose or ear

Question 17

Where does the pituitary gland lie

Answer 17

It lies in the hypophyseal fossa (deepest part of the sella turcica) in the middle cranial fossa

Question 18

What is the function of arachnoid granulations

Answer 18

Returning CSF to the venous circulations

Question 19

What is the function of the buttresses in the bone structure of the skull

Answer 19

These are thicker portions of cranial bone ( pillars) that transmit forces around weaker regions of the cranium
- bypassing orbits and nasal cavity

Question 20

What are the cranial meninges

Answer 20

They are membranous layers that help in the protection of the brain

Including ;
Dura Mater
Arachnoid mater
Pia mater

Question 21

What is the outermost layer of the cranial meninges and what is its two layers ( where are these two layers separate )

Answer 21

Dura mater

It has two layers
- periosteal layer which is connected to the bone
- meningeal layer which is isn contact with the arachnoid layer

These two layers are separate at the venous sinuses and the dura folds

Question 22

The second layer of the meninges is the arachnoid mater, why does it have the spider web appearance

Answer 22

It is attached to the pia mater by tubercles which give it the spider like appearance

These tubercles extend cross the subarachnoid space and are continuous with the pia mater

Question 23

What is the subarachnoid space

Answer 23

It is a fluid filled space which contains CSF and blood vessels, provides a bit of cushioning for the brain.

Question 24

Arachnoid villi are responsible for the resorption of CSF into the venous system, collections o these villi are called what and where can they be found

Answer 24

Collections of arachnoid villi can be found in the saggital sinus and lateral lacunae - these collections are known as arachnoid granulations

Question 25

What it the thin membrane which is attached to the surface of the brain called?

Answer 25

Pia mater

Question 26

What is the purpose of the dura mater folds

Answer 26

They limit the movement of the brain within the cavity
- they follow the fissures and anchor the brain in the skull

For example if there was a blunt force trauma there is something to hold the brain into place

Question 27

Which dura mater fold covers the sella turcia and is the roof over the pituitary fossa

Answer 27

The flax cerebri

Question 28

In which dura mater fold does the venous sinus run

Answer 28

Falx cerebelli - this fold runs in between the nodes of the cerebellum

Question 29

What is the main blood supply of the dura mater

Answer 29

The meningeal Arteries - in particular the middle

Question 30

The herpes zoster virus may lie dormant in ganglia of nerves and then become active again what is the most common nerve for it to affect

Answer 30

Supra-orbital nerve