8: Anatomy - Space-occupying lesions Flashcards
The cranial vault has a ___ volume.
fixed volume
so as volume decreases e.g swelling, bleeding; pressure increases
What is a space occupying lesion?
Some sort of abnormal tissue taking up space in the brain
What may increase as a result of a space occupying lesion?
Intracranial pressure
What may occur if intracranial pressure gets too high?
Herniation
What is the pterion?
H shaped suture where frontal, parietal, temporal and sphenoid borders meet
Thinnest part of the skull
What is notable about the pterion?
Thinnest part of the skull
Which blood vessel is found posterior to the pterion?
Middle meningeal artery
What is the middle meningeal artery immediately deep to?
Pterion
What is meningitis?
Bacterial / viral inflammation of the meninges
What are the three layers of meninges surrounding the brain and spinal cord, from superficial to deep?
Dura mater
Arachnoid mater
Pia mater
In which layer of meninges are the dural venous sinuses found?
Dura mater
What spaces are found in the dura mater?
Dural venous sinuses
What space contains cerebrospinal fluid (CSF)?
Subarachnoid space
Where in the meninges is CSF reabsorbed?
Arachnoid granulations
Which layer of meninges is the thinnest and adheres to the brain’s sulci and gyri?
Pia mater
Which sheets of dura mater are found on top of the
a) pituitary gland
b) cerebellum?
a) Diaphragm sellae
b) Tentorium cerebelli
What structures are covered by the
a) diaphragm sellae
b) tentorium cerebelli?
a) Sella turcica and pituitary gland
b) Cerebellum
What passes through the hole in the tentorium cerebelli?
Brainstem
What type of meninges are the tentorium cerebelli and diaphragm sellae made of?
Dura mater
What sheet of dura runs in the midline of the brain, along the plane of the longitudinal fissure, and separates the right and left cerebral hemispheres?
Falx cerebri
Which aspect of the ethmoid bone is the falx cerebri attached to?
Crista galli
What are the two dural venous sinuses running from the anterior to posterior of the brain?
Superior and inferior sagittal sinuses
Which dural venous sinuses drains blood into the internal jugular vein?
Sigmoid sinuses
Which blood vessels drain blood from the brain into the superior and inferior sagittal sinuses?
Cerebral veins
At which structure do many of the brain’s sinuses meet?
Confluence of the sinuses
Which bony landmark acts as
a) an attachment for the falx cerebri
b) the site of the confluence of the sinuses?
a) Crista galli of ethmoid bone
b) Internal occipital protruberance
Why is part of the face known as the danger triangle?
Facial vein anastomoses with ophthalmic vein, which drains into the cavernous sinuses
So infection from the face can track back into the meninges and cause meningitis
What are the first branches coming off the aorta?
Right and left coronary arteries
Which artery does the vertebral artery come from?
Subclavian artery
Which structure, found only in cervical vertebrae, do the vertebral arteries pass through?
Transverse foramen
How do the vertebral arteries reach the cranial cavity from the aorta?
Subclavian artery
Ascend through transverse foraminae of cervical vertebrae
Ascend through foramen magnum
Which hole do vertebral arteries use to reach the cranial cavity?
Foramen magnum
How does the internal carotid artery reach the brain?
Carotid canal
Which carotid arteries supply the
a) neck, face and scalp
b) brain?
a) External carotid artery
b) Internal carotid artery
Which anastomosis of arteries supplies much of the brain?
Circle of Willis
The Circle of Willis is an anastomosis of arteries from which root arteries?
Left and right vertebral arteries
Left and right internal carotid arteries
Which specific arteries supply the
a) medial
b) lateral
c) posterior
aspects of the cerebral hemispheres?
a) Anterior cerebral artery
b) Middle cerebral artery
c) Posterior cerebral artery
In which space are the cerebral arteries found?
Subarachnoid space
Where is CSF produced?
Choroid plexuses of each ventricle
Where is CSF reabsorbed?
Arachnoid granulations
At which vertebral levels can a lumbar puncture be carried out?
L3/4
L4/5
At which level does the spinal cord end?
L2
The Circle of Willis is found (superior / inferior) to the pituitary gland.
inferior
What path does CSF take from the lateral ventricles to the dural venous sinuses?
1. Produced in choroid plexus
2. Passes from lateral ventricles to 3rd ventricle
3. Passes from 3rd ventricle to 4th ventricle
4. +/- Spinal cord
5. Reabsorbed into dural venous sinuses by arachnoid granulations
How does CSF get from the lateral ventricles to the 3rd ventricle?
Foramen of Monro
(on each side)
Through which passages does CSF get from
a) lateral to 3rd ventricle
b) 3rd to 4th ventricle
c) 4th ventricle to spinal cord?
a) Foramen of Monro
b) Cerebral aqueduct
c) Central canal
What clinical condition is caused by an increased volume of CSF in the ventricles?
Hydrocephalus
Where does blood go in an extradural haemorrhage?
Between the bone of the skull and the dura
Which artery may be damaged by trauma to the pterion, causing an extradural haemorrhage?
Middle meningeal artery
Where does blood go in a subdural haemorrhage?
Between the dura and the arachnoid
Where does blood go in a subarachnoid haemorrhage?
Into the subarachnoid space
What is a haemorrhage affecting the Circle of Willis called?
Berry aneurysm
What is a Berry aneurysm?
Haemorrhage into subarachnoid space caused by damage to Circle of Willis
What can happen to brain tissue if ICP increases?
Herniation
