Week 1 Review

cruciate ligament

cruciate ligament

holds dens in place during rotation of head

longitudinal and transverse bands

PREVENTS POSTERIOR DISLOCATION OF DENS

apical ligament

deep to cruciate

attaches dens to skull

alar ligament

laterally attaches dens to skull

Thoracic vs lumbar vs cervical

cervical- transverse foramen

thoracic- pointed down spinous process, articular facets for ribs, rounded vert body

lumbar-more square spinous process, oval vert body

where do cervical nerves exit

Exit above their respective vert body

except C8

where do non-cervical nerves exit

emerge below vertebral body

at birth, spinal cord ends at

L3

adult spinal cord ends at

bottom of L1/ top of L2

where does adult dura mater end

S2

what does the cauda equina contain

dorsal and ventral roots

what are the 3 layers of spinal membranes

dura mater (subdural matter)

arachnoid mater (subarachnoid/CSF)

pia mater

What do the denticulate ligaments do

separates the ventral and dorsal rootlets from each other

what are denticulate lig composed of

extensions of pia mater

dorsal rami supplies

medial branch - post cutaneous branch

lateral branch- intrinsic muscles of back

ventral ramus supplies

anterior and lateral cutaneous branches

extrinsic muscles of back

where is lumbar puncture done

L3-L4, enters subarachnoid space

spinal cord ends at L2

(where CSF is stored)

Extradural space contains

aka epidural (around dura mater)

epidural fat, internal vert venous plexuses

where does lumbar epidural anesthesia go?

into sacral hiatus

want it below S2 because that is where dura mater ends

main blood supply for spinal cord

anterior and superior spinal arteries

what is significant about lumbar veins

no valves, easy spread of cancer to cranial level

L4-5 disc compression pain/numbness

pain over sacroiliac joint, hip, lateral thigh/leg

numbness on first 3 toes

L4-5 leads to loss of

dorsiflexion of great toe and foot, difficulty walking on heels, foot drop (deep fibular nerve)

internal hamstring reflex diminished

L5-S1 disc compression pain/numbness

pain over sacroiliac joint, hip, posterolateral thigh/leg-heel

numbness on back of calf, lateral heel, foot to 5th toe

L5-S1 disc compression loss of

plantar flexion and great toe may be affected (tibial nerve), difficulty walking on toes

muscle mass of triceps surae

ankle jerk diminished

lumbar laminectomy used to

relieve pressure, due to disc herniation

gray matter vs white matter

gray matter: cell bodies

white matter: myelinated and unmyelinated axons that ascend to brain and descend through spinal cord

purpose of gray and white rami communicantes

distribute sympathetic fibers that will emerge from T1-L2 to respective areas

form symp ganglion that descend or ascend or travel at same level to various organs

ganglia

collection of nerve cell bodies in PNS

Cardiopulmonary plexus

supplies heart, sympathetic outflow

T1-T4

Pain during heart attack

referred pain at left arm, jaw, left chest

due to dermatomal distribution of T1-T4 cardiopulmonary plexus

significance of herpes zoster

varicella zoster virus reactivates from latent state in posterior dorsal root ganglion

shingles rash on skin along dermatome

3 main plexuses

cervical, brachial, lumbosacral

What forms a sacral plexus

ventral rami —> peripheral nerves —> motor

dorsal will receive sensory info

Erbs palsy affect what region of nerve

C5, C6, C7 upper brachial plexus (mostly C5 and 6)

cause of erbs palsy

increase of angle between neck and shoulder —> rupture of fibers from C5, C6, C7 (mostly C6 and C7)

erbs palsy presentation

sensory loss along lateral border of arm, affects entire arm

arm adducted and internally rotated, forearm extended and pronated

klumpkes palsy affects

C8/T1 of brachial plexus (lower brachial plexus)

cause of klumpkes palsy

excessive upward pull of limb

cervical rib can cause compression of lower fibers of brachial plexus

klumpkes presentation

loss of all intrinsic hand muscles- ulnar and medial

sensory loss along medial border and hand and forearm and arm

cartilage in lumbar disc

hyaline

outer annulus fibrosis made of

collagen type I

inner nucleus pulposus made of

type II collagen, PG molecules, water

blood supply to lumbar vertebrae

avascular!

function of nucleus pulposus

resist compressive loads through hydrostatic forces

function of annulus pulposus

resist tensile/torsional loads

if a disc degenerates, load can transfer to

zygapophyseal joints —> spondylolisthesis

lumbar radiculopathy

pain that radiates down leg in specific dermatomal distribution

red flags of radiculopathy —> urgent MRI

bowel or bladder dysfunction

fever chills

known malignancy/metastases

saddle anesthesia

supine straight leg test for

L4-S1 radiculopathy

seated straight leg test

modified supine straight leg

L4-S1

contralateral straight leg test

raising asymptomatic causes pain in symptomatic leg

lasegue test

hip flexed, knee flexion relieves leg symptoms

femoral tension sign

prone, knee passively flexed with hip extended

L2-L4 radiculopathy

timeline of disc herniation healing

improvement in 3 months for 90%

macrophage phagocytosis (3-6 mnths)

12 mnths most symptoms reside w conservative tx

conservative tx of disc herniation

NSAID

PT

corticosteroid

roof of carpal tunnel

transverse carpal ligament aka flexor retinaculum palmar side

muscular effects of carpal tunnel

thenar muscles eventually waste away

muscle weakness —> fine motor tasks difficult

carpal tunnel effect on palm

none, palmar branch upstream and does not enter carpal tunnel so palm unaffected r

risk factors for carpal tunnel

repetitive stress

obesity

pregnancy

underlying conditions like RA

phalens test

flex wrists and hold together for 1 min —> sx of carpal tunnel

tinels sign

tapping transverse carpal ligaments —> sx of tingling, carpal tunnel sx

durkans test

manually compress transverse carpal ligament for 30 seconds —> sx of carpal tunnel

tx of carpal tunnel

behavior mod

PT

splinting

corticosteroids

surgical division of transverse carpal ligament

opioid receptors 3 types

mu, kappa delta

inhibitory neuron in opioid pathway

secrete neurotransmitters signaling other neuron to NOT secrete dopamine

when opioid binds to receptors, this is inhibited —> other neuron secretes dopamine

theories of tolerance to opioids

less sensitive receptors

downregulation (fewer receptors available for binding)

opioids effects

dec HR, BP, wakefulness, respiratory rate

what drugs used to help wean off opioid

methadone (full ag) and buprenorphine (partial ag)- opioid agonists that avoid euphoria sensation

spondylolysis

defect/break in pars interarticularis (aka pars defect)

what typically causes spondylolysis

stress fx/overuse injury in children and adolescents

spondylolisthesis

spondylolysis + anterior slippage of vertebra in relation to vertebra below

break in pars —> disruption of structural integrity of vertebra (grade 1-4)

multipolar neurons have _____

2 or more dendrites, 1 axon

bipolar neurons have _____

1 dendrite, 1 axon

unipolar/pseudounipolar neurons have _____

1 process that splits into 2 “axons”

anaxonic neurons have _____

many dendrites, no axon

CNS supporting cells

astrocytes

oligodendrocytes

microglia

ependymal cells

microglia

macrophages of CNS

engulf infectious/foreign substance

astrocytes

support neurons (CNS)

BBB

structural support

replicates to occupy space of dying neurons

ependymal cells

cover ventricles and central canal (CNS)

CSF pdn and circ

line ventricles of brain and central canal of spinal cord

PNS supporting cells

satellite

schwann

Satellite cells

PNS

electrical insulation of cell bodies

reg nutrient/waste for cell bodies in ganglia

schwann cells

make myelin (PNS)

aka neurolemmocyte

wrap around axon —> faster propagation

oligodendrocytes

make myelin for CNS axons —> faster propagation

unmyelinated axons

smaller diameter —> slower prop

single wrap of schwann cell

oligodendrocyte vs schwann cells

oligo- CNS, sends out multiple process to myelinate more than one axon

schwann- PNS, only one axon

Nerve needs ____ to regenerate

cell body (only in PNS, no regeneration in CNS)

wallerian degeneration

idk what this is

anterograde axonal transport

kinesin - to + end

moves along microtubules

retrograde axonal transport

dynein + to -

moves along microtubules

types of synapses

Electrical (ions)

chemical (neurotransmitters)

Types of synapse depending on where they terminate with regard to another cell

axodendritic

axosomatic

axoaxonic

how to differentiate between neurotransmitter vesicles

small clear (cholinergic, acetylcholine)

small dense (adrenergic, norepi)

large dense (substance P)

vesicle at motor end plate

cholinergic (small clear) e

epi vs peri vs endoneurium

epineurium: around whole nerve

peri: around fascicle

endo: around single process (axon)

when does notochord develop

end of 3rd week

what is the notochord

solid rod like mesodermal structure that extends from head to tail region of embryo

becomes nucleus pulposus

the notochord does not form the

vertebral column!

vertebral column forms AROUND notochord

the notochord induces

the overlying ectoderm to form neural plate, which eventually forms the neural tube —> CNS and spinal cord

abnormal persistence of the notochord gives rise to

malignant tumor (chordoma)

neurulation

formation of neural tube

induced by notochord and paraxial mesoderm —> overlying ectoderm differentiates into thickened plate