Anatomy of Space Occupying Lesions Flashcards
Can the skull expand?
Not really = more able to do it when younger, capable of slow rate expansion
Do the base of skull foraminae allow the contents of the skull to escape?
Not really
What is a space occupying lesion?
Abnormal tissue taking up space = acute or subacute intracranial pathologies can be considered SOLs
What can space occupying limits result in?
Raised ICP = can lead to herniation
What gives sensory innervation to the dura mater?
Mostly CN V
What does the dura mater adhere to?
The internal aspect of the skull
What are the two layers of the dura mater?
Peri-ostial layer = layer closest to bone
Meningeal layer = attached to the arachnoid mater
What is the diaphragm sellae?
Tough sheet of dura mater forming a roof over the pituitary fossa
What is the tentorium cerebelli?
Sheet of dura mater tenting over the cerebellum = attaches to ridges of petrous temporal bones and has central gap for the brainstem
What is the falx cerebri?
Midline structure made of dura mater = separates right and left cerebral hemispheres
What are the attachments of the falx cerebri to the deep aspects of the skull?
Anteriorly = crista gali of ethmoid bone Posteriorly = internal aspect of sagittal suture, internal occipital protuberance
Where do the cerebral veins drain blood from?
Drain venous blood from brain into dural venous sinuses
Where is the confluence of sinuses in the brain?
In the midline at the lateral occipital protuberance
What are some features of the sigmoid sinus?
S shaped
Ends at the jugular foramen
How do you treat hydrocephalus?
Using a ventricular peritoneal shunt
Where does the external carotid artery supply?
Stays outside cranial cavity to supply to neck, face and scalp
How does the internal carotid artery enter the cranial cavity to supply the brain?
Via the carotid canal
How does the vertebral artery enter the cranial cavity?
Passes through the transverse foraminae in the first six cervical vertebrae then through the foramen magnum
Where is the arterial supply to the brainstem and cerebellum located?
Inferior to midbrain, closely related to the pituitary stalk and optic chiasm within the subarachnoid space
Where do the posterior cerebral arteries supply?
Most of the inferior aspect of the brain and the cerebellum
What artery supplies the visual cortex?
The right posterior cerebral artery
Where do the middle cerebral arteries supply?
Lateral aspect of the brain and the temporal lobe
Where do the anterior cerebral arteries supply?
The medial aspect of the brain and the frontal lobe
What are the terminal branches of the internal carotid artery?
Anterior and middle cerebral arteries
What surrounds the Circle of Willis?
Cerebrospinal fluid
What forms the basilar artery?
The left and right vertebral arteries
What are some features of an extradural haemorrhage?
Between the bone and dura
May be due to ruptured meningeal artery or trauma to pterion
What are some features of a subdural haemorrhage?
Into epidural space between dura and arachnoid
Due to torn cerebral veins
May have been caused by fall in the elderly
What are some features of a subarachnoid haemorrhage?
Into CSF of the subarachnoid space
May be due to ruptured Circle of Willis (berry) aneurysm or congenital aneurysm
What are the potential patterns of infratentorial herniation?
Upward
Downward/tonsillar = cerebellar tonsils herniate into foramen magnum
What are the potential patterns of supratentorial herniation?
Cingulate, central, transcavarial, uncal/transtentorial
What occurs in an uncal supratentorial herniation?
Uncus of temporal lobe herniates inferior to tentorium cerebelli = compresses CN III to cause ipsilateral fixed pupil
