Clinical Anatomy of Space Occupying Lesions Flashcards
The word scalp comes from the five layers that make up the structure of the scalp, what are these layers?
S= skin C= connective tissue A= aponeurosis L= loose connective tissue P= pericranium
First three layers of the scalp are often clinically referred to as _____________
the scalp proper as they are very tightly attached to each other (so in craniotomy the three layers will stay together)
Which layer of the scalp contains the arteries?
Connective tissue layer (layer C!)
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_________
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
What is meant by sutures of the skull minimise propagation?
help prevent skull fractures from spreading
Ie fractures should stop when they reach a suture but if enough force fractures can jump sutures
Describe the calvaria?
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
The pterion is the ______ part of the skull and is where _________ bones combine
thinnest
frontal, temporal, parietal, sphenoid
What artery runs directly deep to the pterion?
The middle meningeal artery
What can happen if there is a fracture of the pterion?
Damage the middle meningeal artery which can cause an extradural haemorrhage
Where does the falx cerebri attach to?
the crista galli which is the upper part of the perpendicular plate of the ethmoid bone
What is the diaphragm sellae?
tough sheet of dura mater forming a roof over pituitary fossa
What is the name given to the tough sheet of dura mater forming a roof over pituitary fossa?
diaphragm sellae
What nerves innervate the dura?
Most comes from trigeminal but some does come from vagus
What is the tentorium cerebelli?
- 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
Describe what the falx cerebri is?
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
Venous drainage of the brain is by _______
dural venous sinuses
In some layers dura and periosteal layer are separated and form passages called ____________
dural venous sinuses
Dural venous sinuses drain into _____
the internal jugular veins
Why is pia mater called pia mater?
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.
What are three types of bleeding that may occur within the cranial cavity?
Extradural haemorrhage
Subdural haemorrhage
Subarachnoid haemorrhage
Describe what occurs in an extradural haemorrhage?
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
Describe what occurs in a subdural haemorrhage?
blood separates the dura from the arachnoid
common in falls in the elderly
Describe what occurs in a subarachnoid haemorrhage?
bleeding into the CSF of the subarachnoid space
ruptured Circle of Willis (“berry”) aneurysm
congenital aneurysm
