Spinal Cord Flashcards
at what level does the spinal cord end?
L1
what is the cervical enlargement?
tube is wider in the cervical region where there are more nerves (cervical plexus)
where does the SC begin?
at the foramen magnum
what is the name for the end of the spinal cord?
conus medullaris
pointy end of the spinal cord
what is cauda equina?
the descending bundle of the spinal nerve roots from the conus medullaris
resembles the tail of a horse
nerves then go down to their respective segments (SC ends at L1)
what is the filum terminal?
the pia mater at the end of the SC (conus medullaris) continues caudally as a CT filament
anchors itself to the dura mater
what is the lumbar enlargement?
tube is wider where the lumbar plexus is
name the meninges from inside to out:
pia mater (adheres to cord tightly- like skin)
arachnoid mater
dura mater
what is the denticulate ligament?
attaches via dura mater to bone
stabilizes SC in spine to prevent movement
subarachnoid space is filled with?
CSF
where you do the spinal tap
if you hit cauda equina, only hitting peripheral nerves so damage isn’t permanent
how many pairs of SNs?
31 pairs
8 cervical - cervical & brachial plexus 12 thoracic- thoracolumbar plexus 5 lumbar- lumbar plexus 5 sacral- sacral plexus 1 coccygeal
what is the butterfly made of?
gray mater from the mantle layer
what surrounds the “butterfly”?
white matter from the marginal layer
what is the dorsal horn?
alar plate
sensory
what is the ventral horn?
basal plate
motor
what is the lateral horn?
only in thoracic and sacral ((S1-3)
not very prominent
what are nuclei?
in a transverse section of the SC, the gray matter can be subdivided into groups of neuronal cell bodies call nuclei
what are laminae?
when the SC is cut along its length, nuclei can are seen to be longitudinal CELL COLUMNS
layers or laminae, arranged from dorsal to ventral within the gray matter
Rexed divided the cord into 10 laminae
each lamina extends the length of the cord
lamina I is the most dorsal part of the dorsal horn
lamina IX is the most ventral part of the ventral horn
lamina X surrounds the central canal
which laminae are confined to the dorsal horn? and what do they do?
I - VI
cells in these laminae receive and transmit information concerning sensory input from the spinal nerve afferents
fiber pathways from other SC levels and the brain also synapse on cells in these laminae
lamina I:
Marginal zone (postmarginal nucleus)
sensory relay area for pain & temperature
contributes some fibers to LSTT (lateral spinothalamic thalamus tract)
lamina II:
Substantia Gelatinosa
receives afferent info (pain) from unmyelinated & thinly myelinated afferent fibers & temperature
receives info from higher centers (brain stem)
modulating function
Lamina III - IV
Nucleus proprius
sensory processing
similar to lamina II but also receives input from touch afferents
penetrated by dendrites of large neurons in lamina V
Lamina V
receives afferent fibers and interneurons from II, III, & IV
receives fibers from Corticospinal & ruprospinal tracts
Lamina VI
receives primary proprioceptive input from muscles & tendons
Lamina VII
Clarke’s nucleus (thoracic & upper lumbar)
Intermediolateral nucleus (lateral cell horn)
Intermediomedial nucleus (Visceral afferents)
located in the intermediate gray area and extends into the anterior horn - contains the nucleus dorsalis, intermediolateral & intermediomedial cell columns
Lamina VIII:
fibers from (minor) descending tracts
located in the ventral horn and contains many neurons that send commissural axons to the opposite side of the SC
Lamina IX:
Anterior horn cells (alpha & gamma motoneurons)
motor nuclei- innervate skeletal muscles
confined to the ventral horn and consists of several different coloumns of cells. each of these cell columns contains alpha, beta, and gamma motoneurons which send their axons into the ventral roots of the spinal nerves and innervate skeletal muscles
Lamina X:
surrounds the central canal
interneurons
lamina I, II, and III are primarily ..
pain and temperature
lamina IV, V, and VI are primarily..
touch, pressure and other large afferent systems
slide 7 of SC
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