Spinal Cord and Spinal Nerves Flashcards
spinal cord begins…
medulla
pia mater continues as …
filum terminale internus
median sulcus at midline is ….
posterior/dorsal
where do the dorsal roots enter the spinal cord?
posterolateral sulcus
Where do the ventral roots exit the spinal cord?
anterolateral sulcus
dorsal and ventral roots fuse laterally to become that segment’s … which pass in/out between adjacent vertebrae.
spinal nerve
White matter has …nerve fibers.
myelinated
gray matter has …nerve fibers. It is the neuron ….
unmyelinated; cell bodies
white matter contains 3 columns…
- dorsal
- lateral
- ventral
gray matter has 2 main horns and 1 horn that is only present in certain areas.
- dorsal horn
- ventral horn
- lateral horns
Where are lateral horns not present?
cervical and L4/L5
lateral horns have …motor neurons at …-…. (sympathetic) and ….(parasympathetic).
autonomic, T1-L2 and S2,3,4
how many cervical nerves?
8
how many thoracic nerve segments?
13
how many lumbar nerve segments?
5
how many sacral nerve segments?
5
how many coccygeal segments?
1
how many pairs of spinal cord segments and spinal nerves?
31
cervical nerves run ….their vertebra and thoracic, lumbar, sacral nerves run ….their vertebra
above, under
dorsal roots contain ….fibers from primary sensory neurons.
afferent (sensory)
dorsal root ganglia contain … neuron cell body; which systems?
primary; somatic and autonomic
ventral roots contain mainly …fibers including…
efferent (motor); somatic and autonomic
dorsal primary ramus
toward back
ventral primary ramus
toward belly
4 plexuses
cervical (C1-C4); Brachial (C5-T1); lumbar (L1-L4); sacral (L4-S4)
no …dermatome.
C1
C5 dermatome
clavicle
T4 dermatome
nipple
T10 dermatome
umbilicus
L1 dermatome
inguinal ligament
What nerve give face/forehead sensation?
CN 5
cervical white matter is ….than gray.
greater
sacral white matter is …than gray.
less
more gray matter as we go…
down the spine
ascending white matter pathways (7)
- fasciculus gracilis
- fasciculus cuneatus
- posterior spinocerebellar
- lateral spinothalamic
- anterior spinocerebellar
- spinotectal
- anterior spinothalamic
descending white matter pathways (6)
- lateral corticospinal
- rubrospinal
- anterior coricospinal
- reticulospinal
- vestibulospinal
- tectospinal
DRG houses cell bodies of the ….order sensory neurons.
first
dorsal columns ascend and cross in the ….
lower medulla
anterolateral pathways cross midline ….
immediately at the segment where they enter the spinal cord
Dorsal Column Tract: 1st order sensory neuron..... enters spinal cord via .... ...for lower half of body and ...for upper half. 2nd order sensory neuron.... crosses over via .... 3rd order neuron dorsal column tract is for....
dorsal root ganglia
dorsal root
fasciculus gracilis
fasciculus cuneatus
synapses at lower medulla on gracile and cuneate nuclei.
lemniscal decussation
synapses at somatosensory cerebral cortex
sensation of touch, vibration, 2 point discrimination and propioception
Spinothalamic Tract:
1st order sensory neuron…enters spinal cord via…forms … and ascends ….synapses on 2nd order neurons in….crosses midline at this segment to form… and …
the third order neuron synapses at
….cerebral cortex
receptor in periphery cell in DRG; dorsal root
Lissauer’s track
ipsilaterally two segments
dorsal horns
anterior spinothalamic tract and lateral spinothalamic
thalamus
somatosensory
anterior spinothalamic tract is for…
light touch
lateral spinothalamic tract is for…
localized pain and temperature
if there is an injury at the medulla how does that effect the two pathways?
function of both pathways will be impaired contralateral to the lesion
if there is an injury below the medulla how does that effect the two pathways?
ipsilateral impairment for dorsal column: fine touch, vibration, 2point discrimination, conscious proprioception.
contralateral impairment for spinothalamic: alerting and arousal system: light touch, localized pain and temperature
descending motor fibers: upper body motor neurons
lateral and anterior corticospinal
anterior corticospinal tract has …. number of fibers
small
lateral corticospinal tract has …number of fibers
large
alpha motor neurons innervate
muscle fibers
gamma motor neurons innervate
muscle spindles
corticospinal tract controls…
voluntary, high skill and fractionated movement
corticospinal tract starts…comes down to…crosses at…. into…and synapses with in the…on…
cerebral cortex (upper motor neurons) medulla lower medulla to contralateral side lateral and anterior tracts ventral horn lower motor neurons ventral horn lower motor neurons
lateral corticospinal tract …%cross the midline and on anterior …% descent and do not cross at medulla
90
10
autonomic nervous system coordinates activity of….and…
sympathetic, parasympathetic and enteric (visceral) systems
sympathetic nervous systems comes out of which spinal segments?
T1-L2
parasympathetic nervous system come out of which cranial nerves and spinal segments?
CN 3, 7, 11, 10
S2,3,4
lateral corticospinal tract’s function
fine motor function
origin of lateral corticospinal tract
motor and premotor cortex
ending of lateral corticospinal tract
anterior horn cells (interneurons and lower motor neurons)
location in cord of lateral corticospinal tract
lateral column (crosses medulla at pyramidal decussion)
small central lesion …
loss of pain and temperature sensation but maintained vibration and position sense
large central lesion…
same as small plus loss of lower motor function
complete hemisection..
brown-sequard syndrome
stretch reflex comes from
L3 (L2/L4)
golgi tendon organs and muscle spindles are both part of …
spinocerebellar tract
muscle spindle stretch receptor within…
skeletal muscle
GTO pressure within
tendons
GTO has …. pathways to cerebellum are the ….tracts. they are involved in the cerebellar …..
ascending or afferent
dorsal and ventral spinocerebellar tracts
regulation of movement
lower motor neuron lesions includes
cranial nerves with motor functions
lower motor lesions can cause
flaccid paralysis, reduced muscle tone, muscle atrophy
upper motor neuron lesions causes
increased tone and weakness, hyperactive deep tendon reflexes, no muscle atrophy
