Neurosurgery Flashcards
2 structural divisions of nervous system
CNS: brain/spinal cord
PNS: sensory/motor neurons
2 functional divisions of nervous system
somatic/voluntary: sensory and motor
autonomic: involuntary, viscera + smooth muscle
2 divisions of autonomic nervous system
sympathetic: fight or flight
parasympathetic: calming
8 bones of cranium
2 parietal
2 temporal
frontal
occipital
sphenoid
ethmoid
foramen magnum
opening in occipital bone where spinal cord passes through
3 cranial fossae
anterior: circle of willis
middle: temporal lobes, pituitary, inner + middle ear structures
posterior: occipital lobes, cerebellum, brainstem
3 meningeal membranes
dura: superficial, tough, white
arachnoid: middle, thin, avascular
pia: inner, transparent, adhered to surface of cord and brain
subarachnoid space
CSF between arachnoid and pia maters
principal lobes of cerebrum
frontal
parietal
temporal
occipital
3 structures of brainstem
midbrain
pons
medulla oblongata
ventricular flow
lateral –> monroe –> 3rd ventricles –> cerebral aqueduct –> 4th ventricle –> lushka, magendie –> basal cisterns (arachnoid villi)
where is CSF formed
choroid plexus (ependymal cells)
most in lateral ventricles
where is CSF absorbed
arachnoid villi in dural venous sinuses
into venous circulation
CSF volume in an adult
80-150ml
CSF pressure
10-20mmHg
70-200 mmH2O
vertebrae in spinal column
33
spinal nerves in column
31
what level does spinal cord terminate
L1-L3
cauda equina
near vertical continuation of spinal nerves from end of cord
5 paraspinal ligaments
anterior + posterior longitudinal
interspinal
supraspinal
ligamentum flavum
intervertebral disk
outer annulus fibrosis
inner nucleus pulposis
shock absorber
ruptured intervertebral disk
annulus fibrosis ruptures, nucleus pulposis protrudes through
disk fragment compresses nerves
how does a ruptured disk produce symptoms
nerve compression
1-6 cranial nerves
1 olfactory
2 optic
3 oculomotor
4 trochlear
5 trigeminal
6 abducens
7-12 cranial nerves
7 facial
8 vestibulocochlear/acoustic/auditory
9 glossopharyngeal
10 vagus
11 spinal accessory
12 hypoglossal
cranial nerve for sight
2 optic
cranial nerve for hearing/balance
7 vestibulocochlear/auditory/acoustic
3 cranial nerves for eye movement
3 oculomotor
4 trochlear
6 abducens
cranial nerve for smell
1 olfactory
5 arteries that form circle of willis
anterior, posterior, middle cerebrals
anterior, posterior communicating
function of the circle of willis
blood through cerebral/cerebellar hemispheres
equalize BP
intracranial circulation
arteries that supply circle of willis
r+l internal carotids anteriorly
r+l vertebrals posteriorly
5 common sites of intracranial aneurysm formation
anterior, posterior communicating
anterior, middle, posterior cerebrals
3 most common surgical approaches to circle of willis
frontal
pterional
bifrontal
first sign of ruptured intracranial aneurysm
sudden, severe headache