Chapter 12 Flashcards
Part 1 and 2
the spinal cord is part of the pns or cns
cns
the spinal cord is the major communication between
brain and pns
the spinal cord extends from base of brain to
2nd lumbar vertebrae level
where does the spinal cord taper from
conus medullaris
is the spinal cord wider or thinner at the top ? and how many enlargements
wider , 2 enlargements
what does the spinal cord separate into
cauda equina (horses tail)
cervical enlargement has
nerve fibers to/ form upper limb
lumbosacral enlargement has
nerve fibers to/ from lower limb
the spinal cord is shorter than? and not grow as rapidly during
vertebral column
development
what components does the spinal cord have
cerviccal, thoracic, and sacral
CT strand anchors conus medullaris to 1st coccygeal vertebra (limits superior movement)
filium terminale
the spinal cords gives rise to 31 pair of spinal nerves, and exit vertebrae via
intervertebral and sacral foramina
3 thin ct membranes that cover and protect cns
meninges
what encloses venous sinuses and contains csf dura, arachnoid and pia mater
meningees
what is the epidural space, “tough mother” strong
dura mater
how many layers does the dura mater have
2
deeper meningeal layer. separate to enclose dural venous sinuses
superficial periosteal layer
what dura mater layer forms dural septa
meningeal dura
longitudunal fissure between cerebral hemispheres
falx cerebri
between cerebellar hemisphere
falx cerebelli
transverse fissure between cerebrum U and cerbellum
tentorium cerebelli
subdural space in meninges
arachnoid mater
subarchnoid space
pia mater
spiderweb-like. BV’s and CSF here. what meninge layer
pia mater
what meninges layer absorb CSF into venous blood of sinus
arachnoid mater
“gentle mother” that clings to brain is what meninge layet
pia mater
meningeal inflammation
meningitis
what is meningitis causes by
bacteria or virus
what removes CSF from subarachnoid space
lumbar puncture
antibiotics/ support to prevent spread to CNS
encephalitis
injections into the subarachnooid space go into what
L3/4 and L4/5
where is L3/4 and L4/5
below conus medullaris of spinal cord in cauda equina
subarachnoid space goes to level
S2 of vertebral column
needle is inserted with CSF present and then
nerve fibers move away from needle
meds block AP transmission inject into subarachnoid space
spinal anesthesia (block)
what injection is used to prevent pain in lower body region
spinal anesthesia
advantage of spinal anesthesia block
stronger anesthesia into CSF, faster effect
needle not through dura mater, drugs diffuse into CSF
epirudral anesthesia
advantage of epidural anesthesia
readminister drugs via catheter
spinal cord X-section consists of outer and and deep what
outer white matter
deep gray matter
white matter consists of
myelinated axons-> nerve tracts
gray matter consists of
neuron cell bodies, dendrites and axons
anterior mediam fissure and posterious median sulcus=
separate halves
white matter= 2 columns which are
ventral, dorsal, and lateral
the 3 columns are subdivided into
tracts
collection of axons in CNS, PNS equivalent= nerve
tract
gray matter=
dorsal, ventral, and lateral horn
what connects halves, central canal
gray commisure
what arises from ventral and dorsal root
spinal nerves
dorsal root ganglion house the
sensory cell bodies, afferent
vental is efferent
automatic response to stimulus, no conscious through drives it
reflex
painful stimuli response to minimize damage
protective (somatic reflexes)
what maintains homeostasis= stable BP
autonomic reflexes
reflex arc is in
spinal cord
whats a basic functional unit of NS
reflex
5 steps of AP
stimulus
sensory afferent neuron
integration center
motor efferent neuron
effector
monosynaptic
1 synapse
polysynaptic
> 1 synapse, interneuron
simplest reflex
stretch reflex
patellar tap causes what to stretch
quads
patellar tap causes quads to stretch. muscle spindle receptors in muscles stretch, activating stretch reflex
knee jerk reflex
how is the knee jerk reflex tested
reflex hammer
exaggerated knee jerk reflex response indicated
possibly injury to the brain
diminished knee jerk reflex response indicated
possible injury in spinal cord
what attaches to ends of spindle to allow it to reset to detect further stretch
gamma motor neuron
how does polysynaptic reflex prevent falls
shifting weight
flexor response to painful stimulus
withdrawl reflex
remove body part from stilumus by excitatory interneurons sending message to flexor muscles in lower extremity
withdrawal reflex
simultaneously, the opposite leg has excitatory interneurons stimulating extensor muscles to support the body on 1 leg as injured foot Is withdrawn
crossed extensor relfex
axon is surrounded by what
endoneurium
what kind of CT is endoneurium
delicate loose ct (areolar)
axons are packaged into
fascicle
the fascicle is surrounded by
perineurium
what kind of CT is the peruneurium
dense irregular ct
what is in concentric cell layers, up to 15 layers thick
perineurium
what binds fasicles together to form nerve
epineurium
what CT is epineurium
dense irregular CT
what makes peripeheral nerves tough
CT coverings
spinal nerves are part of the PNS, 31 pair, emanate from the
spinal cord
spinal nerves are named according to where they
emerge from
all except 1st pair and sacral exit vertebrae through
intervertebral foramina (between vertebrae)
C1 exit between
skull and C1 vertebrae
how many nerves in cervical
8
how many nerves are in thoracic
12
how many nerves are in the lumbar
5
how many nerves are in sacral
5
how many nerves are in coccygeal
1
all spinal nerves are mixed what
sensory and motor
spinal nerve roots connect
PNS to spinal cord
spinal roots arise from
longitudial rows or rootlets attached to each side of spinal cord
spinal nerves leave the spinal cord at
anterolateral and posterolateral sulci
spinal nerves become increasingly longer from
superior to inferior cord
cervical=
short, run horizontal
lumbar and sacral=
run inferiorly as cauda equina pre exit of vertebral column
spinal cord has about how many rootlets
8
the 8 rootlets unite to form
ventral or dorsal root of spinal nerve
ventral root=
motor (efferent)
where do ventral roots arise from
ventral horn motor neurons- skeletal muscle
dorsal root=
sensory (afferent)
where do dorsal roots arise from
sensory neurons in dorsal root ganglion- spinal cord
how short are spinal nerves
1-2 cm
spinal nerves quickly branches into
dorsal, ventral ramus, and meningeal branch
what innervates deep muscles of dorsal trunk and also innervates CT and skin near midline back
dorsal rami
ventral rami have how many ways of distribution
2
thoracic region forms what
intercostals nerves, and innervates intercostal muscles and skin of thorax
the remaining spinal nerves from ventral rami form
5 major plexuses
also communicating rami=
thoracic and upper lumbar
spinal cord carry axons asSOCIATED WITH
sympathetic ANS
what is a plexus
intermingling of nerves formed by ventral rami and other spinal nerves
each muscle in limb receives nerve supply from
more than 1 spinal nerve
advantage of plexus
damage 1 spinal segment does not result in complete paralysis
overlap from multiple spinal cord levels minimize
loss of control and feeling to specific body area after a spinal cord injury
ventral rami of spinal cord includes
cervical, brachial, lumbar, sacral, coccygeal
C1-C4
cervical
C5-T1
brachial
L1-L4
lumbar
S5-Co
coccygeal
cervical plexus is deep
in the neck
spinal nerves what for cervical plus
c1-c4
what does the cervical plexus innervate
superficial neck skin and hyoid bone muscle
phrenic nerve is what nerves
C3-C5
what does the phrenic nerve innervate
diaphragm
irritation of the phrenic nerve results in
diaphragm spasms or hiccups
severing of the diaphragm results in
paralyzed diaphragm and respiratory arrest
bracial plexus has how many roots
5
the 5 roots in brachial plexus are deep in
sternocleidomastoid
the 5 roots form
3 trunks, 6 divisions, 3 cords, 5 upper limb nerves
what is in the brachial plexus
axillary, radial, musculocutaneous, ulnar, and median nerve
most easy to damage in brachial plexus
ulnar
is damage to ulnar perm or temp
temp usually
ulnar is what bone
funny bone
severe damage to ulnar results in
unable to male fist, grip= claw hand
numb entire upper limb and inject near plexus is what
brachial anesthesia
injury due
xs arm pull or bloe to superior shoulder
severe injury to brachial plexus =
weaken or paralyze upper limb
what is thoracic outlet syndrome
condition due to compression of brachial plxus or subclavian artery or vein
TOS compression of nerves and vessels in thoracic outlet syndrome is where
lower neck and upper chest
causes of TOS
MVA
repetitive action
pregnancy
anatomical differences
risk factor for TOC
women
age 20-50
S&S for TOC
numbness in arms and fingers
shoulder neck pain
arm fatigue
weak grip
diagnosis for TOC
utrasound, X-ray, MRI
treatment for TOC
PT, antiinflammatory, steriod, surgery
complication for TOC
repetition injury
long term- chronic pain and disability
prevention for TOC
avoid carrying heavy backpack
daily stretch
exercise to keep shoulders strong
lumbosacral plexus spinal nerves l1-l4 lies within
psoas major muscle
femoral nerve is under
inguinal ligament
femoral nerve motor branches to
quads, cutaneous to anterior thigh and medial lower leg
obturator nerve innervates
adductors
sciatic nerve =
tibial and common peroneal nerve L4-S3
whats the largest nerve in the body
sciatic nerve
tinging sensation due to
pressure on sciatic nerve
damage to sciatic nerve is from
herniated disc, hip injury, or bad hip injection
pudenal nerve
innervates area of perineum
what does the pudenal nerve stimulate what and controls what
erection and controls urination
coccygeal innervation
pelvic floor muscles and sensory cutaneous over coccyx skin area
dermatomes of skin innervated by
cutaneous branches of single spinal nerve
all except what contribute to dermatomes
C1
dermatomes help identify
nerves damaged with spinal cord injury
what is spinal stenosis
spinal canal/ nerve root narrowing that causes compression of nerves
spinal stenosis is usually in what area
cervical and lumbar
S&S of spinal stenosis
pain
weak
numbness in back
worse w standing
treatment of spinal stenosis
PT
maintain activity
strengten muscle
steroids
laminectomy= decompression
spinal fusion (last resort)