Anatomy of Space Occupying Lesions Flashcards
define space occupying lesion
abnormal tissue in the brain that is taking up space
2 types of space occupying lesion and an example of each
acute eg brain bleed
subacute eg brain tumour
describe the monroe kellie hypothesis
small increase in ICP will increase intracranial volume massively
name the 5 layers of the scalp
Skin Connective tissue (contains blood supply to scalp) Aponeurosis Loose connective tissue Pericranium
which arteries anastamose to supply the scalp
external carotid and internal carotid arteries
why does a scalp laceration bleed so much
anastamosis of muscle holds wound open
rich blood supply to the scalp
thinnest layer of the scalp?
loose connective tissue
what is a periosteum?
outer layer of bone responsible for bone formation
how many bones are in the skull?
23
why do sutures exist in the skull?
help prevent skull fractures from spreading
what artery exists under the pterion?
middle meningeal artery
start and end point of anterior cranial fossa?
frontal
lesser wings of sphenoid
start and end point of middle cranial fossa?
lesser wings of sphenoid
petrous part of temporal bone
start and end point of posterior cranial fossa
petrous part of temporal bone
occipital bone
sensory nerve supply to dura mater?
CN V
role of the arachnoid granulations in the arachnoid mater?
reabsorb CSF
name the 2 layers of the dura mater and their anatomical relations
periosteal layer (closest to bone) meningeal layer (under the dural venous sinus - closest to arachnoid mater)
what action causes pain in meningitis?
stretching of the dura mater
smallest fold of dura? where is it located?
diaphragm sellae
middle cranial fossa
the diaphragm sellae is located immediately superior to…
the sella turcica
what does the tentorium cerebelli attach to?
ridges of the petrous temporal bones
why is there a gap in the tentorium cerebellae have a gap in it?
to allow the brainstem to pass through
where is the falx cerebri located?
between the cerebral hemispheres in the midline
anterior and posterior attachments of the falx cerebri?
crista galli of ethmoid anteriorly
internal occipital protuberance of the occipital bone posteriorly
which veins are located in the falx cerebri?
superior and inferior sagittal sinus
where do the dural venous sinuses (Esp the sagittal sinuses) join?
the confluence of sinuses
what does the confluence of sinuses drain into?
the right/left sigmoid sinus
what do the sigmoid sinuses become and at what anatomical location?
the internal jugular vein at the jugular foramen
where is the danger triangle of the brain?
front of the face from the forehead down to the top lip
why is the danger triangle called this?
possible route for infection as no valves so an infection can spread to the cavernous sinus eg by squeezing a spot
cerebral veins are mini branches off of what sinuses?
the sagittal sinuses (superior and inferior)
what do cerebral veins do?
drain venous blood into dural venous sinuses
the right posterior cerebral artery supplies…
the posterior aspect of the right cerebral hemisphere
middle cerebral arteries are a branch of…
the internal carotid arteries
anterior cerebral arteries supply…
the medial aspect of the cerebral hemispheres
he posterior cerebral arteries supply..
the posterior aspect of the cerebral hemispheres (1 for each side)
what do the posterior communicating arteries communicate with?
internal carotid arteries
middle cerebral arteries supply?
the lateral aspect of the cerebral hemispheres
opthalmic artery is a branch of…
internal carotid artery
the circle of willis is contained in what meningeal layer?
subarachnoid space
subarachnoid space terminates at…
S2
spinal cord ends at…
L2
the anterior cerebral artery is a branch of..
internal carotid artery
what branch comes off the anterior cerebral artery?
anterior communicating artery
the central canal of the spinal cord is continuous with the __ ventricle
4th
excessive production, obstruction or adequate reabsorption of flow leading to increased CSF volume is defined as…
hydrocephalus
Tx of hydrocephalus
ventricular peroneal shunt
the lateral ventricles are contained in which lobe?
parietal lobe on either side
the middle meningeal artery is contained between what layers?
bone and dura
cerebral veins transverse what layers? why?
arachnoid mater and dura to get to the dural venous sinuses
3 types of haemorrhage
extradural
subdural (below dura)
subarachnoid (bleed into subarachnoid space)
CSF with blood in it suggests a __ haemorrhage
subarachnoid
a subdural haemorrhage will be a result of damage to what veins?
cerebral
an extradural haemorrhage will be a result of damage to what vessel?
middle meningeal artery
first ligaments reached by an epidural catheter from superficial to deep
supraspinous ligament
interspinous ligament
ligamentum flavum
how can an epidural haematoma be caused by an epidural anaesthetic?
damaging the extradural venous plexus which will compress the spinal cord
a lumbar puncture’s final destination is…
subarachnoid space
why is L3/4 used for anaesthesia/samples?
- spinal cord has ended and cauda equina is less easily damaged
- vertebrae haven’t fused yet unlike in the sacral/coccygeal region
R or L cerebral hemisphere herniates under the falx cerebri is an example of what kind of herniation?
cingulate herniation
what happens in uncal herniation
the medial part (uncus) of the temporal lobe herniates inferior to the tentorium cerebelli
which type of herniation involves a herniation through a defect eg fracture
transcalvarial
a downward cerebellar herniation would herniate through…
the foramen magnum
what type of herniation can cause a “blown” (ipsilateral fixed dilated pupil) and why?
uncal
compresses the oculomotor nerve
