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
Bell’s palsy
facial lower motor nerve paralysis
- facial
Meniere’s disease
dizziness, sensation of fullness or pressure in ears
- vestibulocochlear/auditory/acoustic
trigeminal neuralgia
severe pain in the face
- trigeminal
treat tic douloureux
glycerol rhizotomy
radiofrequency
balloon compression
microvascular decompression
carpal tunnel syndrome
compression of the median nerve
how to treat carpal tunnel syndrome
decompression of the median nerve at the wrist
neurectomy
division of the vestibular portion of 8th cranial nerve
treats Meniere’s disease/vertigo
rhizotomy
dissection of a nerve root
sympathectomy
excision of a portion of the autonomic nervous system
neurolysis
freeing a nerve from adhesion
most frequently encountered neurosurgical problem
herniated lumbar disk
laminectomy
meningocele
failure of the union of vertebral areas in fetal development
myelomeningocele
meningocele with neural elements
cerebrospinal rhinorrhea
CSF leak of the nose
cerebrospinal otorrhea
CSF leak of the ear
craniotomy
incision into the skull to expose the brain (flap replaced)
craniectomy
opening into the skull where the bone flap isn’t replaced
craniotomy vs. craniectomy
in craniectomy the bone flap isn’t replaced
why do a craniotomy
intracranial hematoma
control bleeding
debulk/resect a tumor
excise/clip vascular lesions
aspirate abscesses
decompress cranial nerves
why do a craniectomy
remove tumors
hematoma
bone infection
cranioplasty
repair of a skull defect
burr hole
small incision from scalp to brain
minimum exposure
why do a burr hole
remove localized fluid
access ventricles
biopsy
electrode placement
epidural vs subdural hematoma
epidural: arterial bleeding, increased ICP, more common
subdural: slow collection of venous blood
epidural hematoma tear/laceration of what artery
middle meningeal
vessels commonly responsible for subdural hemorrhage
basalar
CHECK
lumbar laminectomy
excision of one or more lumbar lamina
why do a lumbar laminectomy
decompress neural tissue
positions for lumbar laminectomy
prone: most common
modified knee-chest
lateral
frames in lumbar laminectomy
Wilson: prone
lateral: bean bag
Andrews: knee chest
spinal cord stimulator unit
implantable, non destructive device
CHECK
spinal cord stimulator use
chronic intractable pain in trunk/limbs
electrical impulse in epidural space (tingling masks pain)
arteriovenous malformation
abnormal communication between arterial and venous systems; blood vessel tumor
treat AVM
excision/ligation
endovascular embolization
cervical tongs for neck injury
Crutchfield
Garner Wells
Vinke
x-ray of choice for acute head injury
CT scan
methylene blue
marking ink
inflammatory response in CNS tissue
myelography
contract in subarachnoid space (spine)
view cord, roots, column
WADA’s test
before brain surgery to lateralize:
language
memory
dominant hemisphere
seizure/lesion
hydrocephalus
excessive CSF causes dilation of ventricles
external vs internal hydrocephalus
external (communicating): abnormal absorption
internal (non-communicating): obstruction of pathways
2 surgical shunts for hydrocephalus
ventriculoperitoneal
ventriculoatrial
common disposable hemostatic scalp clips
Raney
LeRoy
mechanical hemostasis of galea/skin
3 ways to treat intracranial aneurysms
ligation of feeding vessels with clips
fine silk suture
wrap with muslin PMMA
mechanical hemostasis
physical barrier
patties
clips
gelfoam
surgicel
bone wax
chemical hemostasis
clotting cascade
surgicel
topical thrombin
absorbable collagen/fibrillar
hand-controlled pneumatic driver for burr holes
craniotome
hand-controlled manually-powered driver for burr holes
Hudson Brace
hi-powered foot-controlled pneumatic instrument for turning bone flaps or removing laminae
Midas Rex
Triton
Saber
instrument to remove nucleus pulposis (soft tissue)
pituitary rongeur
instrument to remove bone spurs from intervertebral laminae
kerrison rongeur
CUSA
cavitron ultrasonic surgical aspirator
hi frequency sound waves
CUSA in neuro
debulk/emulsify a tumor
hemostasis and spares other tissue
