Clinical Anatomy of Space Occupying Lesions

Question 1

The word scalp comes from the five layers that make up the structure of the scalp, what are these layers?

Answer 1

S= skin
C= connective tissue
A= aponeurosis
L= loose connective tissue
P= pericranium

Question 2

First three layers of the scalp are often clinically referred to as _____________

Answer 2

the scalp proper as they are very tightly attached to each other (so in craniotomy the three layers will stay together)

Question 3

Which layer of the scalp contains the arteries?

Answer 3

Connective tissue layer (layer C!)

Question 4

Scalp arteries form a rich _____1______ just deep to the skin. The arteries are really well embedded in the _____2________. This means if there are wounds are lacerations they can bleed quite ______3_________

Answer 4

1) anastomotic network
2) dense connective tissue of the second layer of the scalp
3) extensively as the walls of the arteries are being held open by that dense connective tissue

Question 5

What is meant by sutures of the skull minimise propagation?

Answer 5

help prevent skull fractures from spreading

Ie fractures should stop when they reach a suture but if enough force fractures can jump sutures

Question 6

Describe the calvaria?

Answer 6

Top part of the skull. It is the upper part of the neurocranium and covers the cranial cavity containing the brain. It forms the main component of the skull roof. The calvaria is made up of the superior portions of the frontal bone, occipital bone, and parietal bones

Question 7

The pterion is the ______ part of the skull and is where _________ bones combine

Answer 7

thinnest

frontal, temporal, parietal, sphenoid

Question 8

What artery runs directly deep to the pterion?

Answer 8

The middle meningeal artery

Question 9

What can happen if there is a fracture of the pterion?

Answer 9

Damage the middle meningeal artery which can cause an extradural haemorrhage

Question 10

Where does the falx cerebri attach to?

Answer 10

the crista galli which is the upper part of the perpendicular plate of the ethmoid bone

Question 11

What is the diaphragm sellae?

Answer 11

tough sheet of dura mater forming a roof over pituitary fossa

Question 12

What is the name given to the tough sheet of dura mater forming a roof over pituitary fossa?

Answer 12

diaphragm sellae

Question 13

What nerves innervate the dura?

Answer 13

Most comes from trigeminal but some does come from vagus

Question 14

What is the tentorium cerebelli?

Answer 14

• sheet of dura mater “tenting” over the cerebellum
  
  • attaches to the ridges of the petrous temporal bones
  • has a central gap to permit the brainstem to pass through

Question 15

Describe what the falx cerebri is?

Answer 15

Midline structure made of dura mater
Attaches to deep aspect of skull: crista galli of the ethmoid bone anteriorly, internal aspect of the sagittal suture, internal occipital protruberance posteriorly, separates the right & left cerebral hemispheres

Question 16

Venous drainage of the brain is by _______

Answer 16

dural venous sinuses

Question 17

In some layers dura and periosteal layer are separated and form passages called ____________

Answer 17

dural venous sinuses

Question 18

Dural venous sinuses drain into _____

Answer 18

the internal jugular veins

Question 19

Why is pia mater called pia mater?

Answer 19

It means faithful and unlike the arachnoid and dura mater the pia mater follows all the contours of the brain, it goes down into all the gyri etc.

Question 20

What are three types of bleeding that may occur within the cranial cavity?

Answer 20

Extradural haemorrhage
Subdural haemorrhage
Subarachnoid haemorrhage

Question 21

Describe what occurs in an extradural haemorrhage?

Answer 21

between the bone & the dura
may occur with a ruptured middle meningeal artery due to trauma to the pterion
Also known as epidural
Space shouldn’t be there blood creates it

Question 22

Describe what occurs in a subdural haemorrhage?

Answer 22

blood separates the dura from the arachnoid

common in falls in the elderly

Question 23

Describe what occurs in a subarachnoid haemorrhage?

Answer 23

bleeding into the CSF of the subarachnoid space
ruptured Circle of Willis (“berry”) aneurysm
congenital aneurysm