Spinal Cord

Question 1

at what level does the spinal cord end?

Answer 1

L1

Question 2

what is the cervical enlargement?

Answer 2

tube is wider in the cervical region where there are more nerves (cervical plexus)

Question 3

where does the SC begin?

Answer 3

at the foramen magnum

Question 4

what is the name for the end of the spinal cord?

Answer 4

conus medullaris

pointy end of the spinal cord

Question 5

what is cauda equina?

Answer 5

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)

Question 6

what is the filum terminal?

Answer 6

the pia mater at the end of the SC (conus medullaris) continues caudally as a CT filament

anchors itself to the dura mater

Question 7

what is the lumbar enlargement?

Answer 7

tube is wider where the lumbar plexus is

Question 8

name the meninges from inside to out:

Answer 8

pia mater (adheres to cord tightly- like skin)
arachnoid mater
dura mater

Question 9

what is the denticulate ligament?

Answer 9

attaches via dura mater to bone

stabilizes SC in spine to prevent movement

Question 10

subarachnoid space is filled with?

Answer 10

CSF
where you do the spinal tap

if you hit cauda equina, only hitting peripheral nerves so damage isn’t permanent

Question 11

how many pairs of SNs?

Answer 11

31 pairs

8 cervical - cervical & brachial plexus
12 thoracic- thoracolumbar plexus
5 lumbar- lumbar plexus
5 sacral- sacral plexus 
1 coccygeal

Question 12

what is the butterfly made of?

Answer 12

gray mater from the mantle layer

Question 13

what surrounds the “butterfly”?

Answer 13

white matter from the marginal layer

Question 14

what is the dorsal horn?

Answer 14

alar plate

sensory

Question 15

what is the ventral horn?

Answer 15

basal plate

motor

Question 16

what is the lateral horn?

Answer 16

only in thoracic and sacral ((S1-3)

not very prominent

Question 17

what are nuclei?

Answer 17

in a transverse section of the SC, the gray matter can be subdivided into groups of neuronal cell bodies call nuclei

Question 18

what are laminae?

Answer 18

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

Question 19

which laminae are confined to the dorsal horn? and what do they do?

Answer 19

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

Question 20

lamina I:

Answer 20

Marginal zone (postmarginal nucleus)

sensory relay area for pain & temperature

contributes some fibers to LSTT (lateral spinothalamic thalamus tract)

Question 21

lamina II:

Answer 21

Substantia Gelatinosa

receives afferent info (pain) from unmyelinated & thinly myelinated afferent fibers & temperature

receives info from higher centers (brain stem)

modulating function

Question 22

Lamina III - IV

Answer 22

Nucleus proprius

sensory processing

similar to lamina II but also receives input from touch afferents

penetrated by dendrites of large neurons in lamina V

Question 23

Lamina V

Answer 23

receives afferent fibers and interneurons from II, III, & IV

receives fibers from Corticospinal & ruprospinal tracts

Question 24

Lamina VI

Answer 24

receives primary proprioceptive input from muscles & tendons

Question 25

Lamina VII

Answer 25

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

Question 26

Lamina VIII:

Answer 26

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

Question 27

Lamina IX:

Answer 27

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

Question 28

Lamina X:

Answer 28

surrounds the central canal

interneurons

Question 29

lamina I, II, and III are primarily ..

Answer 29

pain and temperature

Question 30

lamina IV, V, and VI are primarily..

Answer 30

touch, pressure and other large afferent systems

Question 31

slide 7 of SC

Answer 31

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