Spinal Cord And Ans

Front 1

The spinal cord is a continuation of what?

Back 1

medulla

Front 2

Where does the spinal cord begin and end?

Back 2

exits from the foramen magnum and ends at L1-2

Front 3

Do spinal cord segments correspond to vertebral segments?

Back 3

no

Front 4

How many pairs of spinal nerves are there?

Back 4

31

Front 5

Discuss the exit of nerves from the vertebra.

Back 5

there are 8 cervical nerves, the first one exits above the atlas, therefore C8 is below C7, for the rest of the spinal cord the nerve exits below the corresponding vertebra

Front 6

What occurs as one moves cranial to caudal w/ regards to spinal nerves?

Back 6

nerves run progressively longer distances within the spinal canal before exiting

Front 7

What does the cervical enlargement accommodate?

Back 7

spinal segments C4 to T1 for brachial plexus

Front 8

Where is the lumbosacral enlargement?

Back 8

from L1 to S3 spinal segments, but T11 to L2 vertebral segments

Front 9

What are the 3 parts of the meninges of the spinal cord?

Back 9

dura, arachnoid and pia mater

Front 10

What is between the dura mater and periosteum?

Back 10

extradural or epidural space

Front 11

Where does the dura mater end?

Back 11

S2

Front 12

What is inside of the dura mater?

Back 12

arachnoid mater and denticulate ligament

Front 13

What is the ribbon-like structure that extends laterally from the midline on each side of the spinal cord? What is its purpose?

Back 13

denticulate ligament
stabilizes the spinal cord within the dura

Front 14

Is the dura free within the vertebral canal?

Back 14

yes

Front 15

What is the dura mater continuous with at the foramen magnum?

Back 15

cranial dura

Front 16

What is located outside of the spinal dura mater? (what makes up the epidural space)

Back 16

fat, arteries, veins, then periosteum

Front 17

What is the characteristic of the arachnoid mater on the dural surface?

Back 17

It is impermeable to most fluid flow and is thus responsdible for containing the cerebral spinal fluid

Front 18

What does the pia mater enclose?

Back 18

the network of blood vessels supplying the spinal cord

Front 19

What is the combination of the pia mater and the inner portion of arachnoid mater that surrounds the brain and spinal cord?

Back 19

leptomeninges

Front 20

Where does the spinal cord end (give its formal name)? Where does the dura mater and subarachnoid space end? What is the name of the area between these 2 areas?

Back 20

L1-2, conus medullaris
S2
from L2 to S2 is the lumbar cisterna

Front 21

What are the 2 parts of the lumbar cisterna?

Back 21

cauda equina
filum terminale

Front 22

What is the name of the spinal nerves that are distal to the conus medullaris?

Back 22

cauda equina

Front 23

What is the strand of CT that extends from the end of the conus medullaris (L2) and attaches inferiorly to the dural sac (S2)?

Back 23

filum terminale

Front 24

What attaches to the periosteium of the coccyx and is located below the dural sac? When it flexes what is the result?

Back 24

filum terminale externa (central ligament)
pulls the spinal cord anteriorly

Front 25

What is the space between the periosteum of the vertebra and the dura mater of the spinal cord?

Back 25

epidural space

Front 26

What is the epidural space surrounded by? (anteriorly, laterally, posteriorly)

Back 26

anteriorly-posterior longitudinal ligament, intervertebral discs and bodies of vertebrae
laterally-periosteum on the pedicles and 48 intervertebral foramen
posteriorly-laminae and ligamentum flavum

Front 27

What occupies the epidural space?

Back 27

fat, loose CT, internal vertebral venous plexus

Front 28

What is the potential space between the dura and the fluid-impermeable portion of the arachnoid layer?

Back 28

subdural space

Front 29

What is the space between the arachnoid layer lining the dura and the arachnoid layer external to the pia? What is it filled with?

Back 29

subarachnoid space
filled w/ CSF and arachnoid trabeculae

Front 30

where is the largest spinal subarachnoid space?

Back 30

caudal to the conus medullaris (L1-2) and cranial to S2

Front 31

What does the CSF serve as?

Back 31

mechanical and protective support for the brain, ion sink, so important for brain excitability

Front 32

Discuss the volume of CSF and its distribution.

Back 32

120-150mL total
95ml within and surrounding brain
35-55ml surrounds spinal cord
about 450-500ml produced daily

Front 33

What is the normal specific gravity and color of CSF?What is its normal pressure?

Back 33

1.007
clear
70-180 mm Hg

Front 34

Where is the majority of CSF produced?

Back 34

choroid plexuses within the lateral third and fourth ventricles

Front 35

Describe the path of CSF.

Back 35

CSF produced in lateral ventricles and passes to the interventricular foramina into the third ventricle, down the cerebral aqueduct into the fourth ventricle and out either the median aperture or two lateral apertures

Front 36

What are subarachnoid cisterns?

Back 36

places where the subarachnoid space is larger

Front 37

What is the cerebellomedullary cistern?

Back 37

the largest subarachnoid space

Front 38

How is CSF absorbed back into the venous blood?

Back 38

through arachnoid villi along the superior sagittal sinus

Front 39

Where is a spinal tap typically done?

Back 39

between L3/L4 or L4/L5

Front 40

List the structures in order that a spinal tap needle must penetrate. (8)

Back 40

-skin
-subcutaneous tissue
-supraspinous ligament (toughest)
-interspinous ligament
-ligamentum flavum (tough)
-fatty tissue and venous blood within dural space
-dura mater (tough)
-arachnoid mater and into subarachnoid space

Front 41

Which nerve, that is resoponsible for innervating the spinal canal, arises from the dorsal ramus? ventral ramus?

Back 41

articular nerves
recurrent meningeal nerves

Front 42

what do articular nerves innervate?

Back 42

facet joint, ligamentum flavum, interspinous ligament, supraspinous ligament

Front 43

Why may it be necessary to block more than a single vertebral level?

Back 43

articular nerves often innervate two vertebral levels

Front 44

What do recurrent meningeal nerves innervate?

Back 44

anterior longitudinal ligament, dorsal longitudinal ligament, vertebral periosteum and dura mater of spinal cord

Front 45

Extrinsic arteries give off arteries that supply blood to the spinal cord. Name them. (6)

Back 45

vertebral artery (branches off subclavian)
ascending cervical branches off inferior thyroid artery
deep cervical artery
posterior intercostal
lumbar
lateral sacral

Front 46

Which arteries supply blood to the vertebrae?

Back 46

radicular

Front 47

Which arteries supply blood to the anterior and posterior spinal arteries?

Back 47

medullary

Front 48

What is the relationship in size of ventral vs dorsal medullary arteries?

Back 48

ventral are larger in diameter

Front 49

All ventral medullary arteries join what?

Back 49

the anterior spinal artery

Front 50

What supplies the spinal cord blood between T8 and L3? What does it arise from?

Back 50

great ventral medullary artery (or major anterior radicular artery) of Adamkiewicz
it arises from the inferior intercostals or superior lumbar arteries

Front 51

When repairing abdominal aneurysms what has helped to protect the spinal cord from ischemia?

Back 51

epidural cooling

Front 52

Three longitudinal arteries run just external to the pia mater in the subarachnoid space. What are they?

Back 52

one anterior spinal artery
two posterior spinal arteries

Front 53

Where does the anterior spinal artery run and what does it supply?

Back 53

runs in the midline and supplies the anterior 2/3 of spinal cord, including most gray matter

Front 54

Where does the anterior spinal artery branch from?

Back 54

verterbral arteries

Front 55

Where do the posterior spinal arteries run and what do they supply?

Back 55

run posterior to the dorsal roots
supply posterior 1/3 of spinal cord

Front 56

Where do the posterior spinal arteries branch from

Back 56

posterior cerebellar arteries

Front 57

How many central arteries are there and where do they branch from?

Back 57

200-300, branch off the anterior longitudinal spinal artery

Front 58

What do central arteries supply?

Back 58

gray mater and anterior 2/3 of spinal cord

Front 59

What do perforating branches off the pia and posterior arterial plexus supply?

Back 59

mainly white matter in posterior 1/3 of spinal cord

Front 60

Name the intrinsic arteries.

Back 60

centarl arteries
perforating branches

Front 61

During repair of lower thoracic and upper lumbar aortic aneurysms the aorta is often clamped above and below the aneurysm. Epidural cooling is used to cool the spinal cord w/ cold saline. What does this do? Why is this important?

Back 61

reduces the metabolic needs of the spinal cord
the great anterior medullary artery of Adamkiewicz loses normal blood flow
helps prevent paralysis

Front 62

What are the intrinsic veins of the spinal cord?

Back 62

central (sulcal) veins
radial veins

Front 63

What do central veins drain?

Back 63

medial ventral gray mater

Front 64

What do radial veins drain?

Back 64

all of the spinal cord minus medial ventral gray mater

Front 65

The anterior spinal veins and three posterior spinal veins located in the extradural space form what?

Back 65

internal vertebral venous plexus

Front 66

The internal vertebral venous plexus receives blood from what?

Back 66

radiculomedullary veins

Front 67

The internal vertebral plexus is valveless and drains where?

Back 67

superiorly into the occipital sinus
also drains into intervertebral veins, ascending lumbar veins, and azygos venous sytem

Front 68

Where does blood leave the epidural space?

Back 68

at intervertebral veins

Front 69

What does the spinal cord connect?

Back 69

CNS to PNS

Front 70

Collections of nerve cell bodies in the spinal cord form what?

Back 70

H-shaped gray matter

Front 71

Which part of the nervous system is responsible for movement and body functions?

Back 71

PNS

Front 72

Which horns are sensory? motor?

Back 72

dorsal
ventral

Front 73

Where does the somatic motor nerve cell body lie? sensory?

Back 73

ventral horn
dorsal root ganglia

Front 74

What is the sectioning of the dorsal or ventral roots of a spinal nerve in order to relieve intractable pain or spastic paralysis?

Back 74

rhizotomy

Front 75

What is the ANS classically defined as?

Back 75

a visceral motor system that modulates internal organ function

Front 76

What are the 2 divisions of the ANS? What part of the spinal cord do they make up?

Back 76

SNS-thoracolumbar
PNS-craniosacral

Front 77

What 2 motor neurons do the SNS and PNS viseral motor systems use?

Back 77

preganglionic nerve
a second postganglionic nerve

Front 78

Where is the preganglionic nerve cell body located?

Back 78

in the CNS

Front 79

Where is the postganglionic nerve cell body located?

Back 79

in a ganglia in the periphery

Front 80

What is a ganglia?

Back 80

aggregation of nerve cell bodies located in the peripheral nervous system

Front 81

What is the function of the SNS? PNS?

Back 81

fight or flight
feed and assimilate

Front 82

Why is it that if you destroy sympathetic nerves you destroy afferent nerves to that organ as well?

Back 82

generally afferent nerves from viscera pass back to the CNS w/ sympathetic nerves

Front 83

In the pelvis, viscera afferents generally pass back to the CNS w/ what type of nerves?

Back 83

parasympathetic

Front 84

Where are preganglionic nerve cell bodies of the SNS located? (what levels)

Back 84

in the intermediolateral column of the spinal cord from T1-L2

Front 85

What are some examples of preganglionic sympathetic nerves that skip the synapsing in the paravertebral chain ganglia and synapse instead on postgaglionic nerves in prevertebral ganglia?

Back 85

celiac, superior and inferior mesenteric prevertebral ganglia

Front 86

What is the preganglionic neurotransmitter for the SNS?

Back 86

acetylcholine

Front 87

What is the postganglionic neurotransmitter for the SNS?

Back 87

norephinephrine

Front 88

Why does generalized sympathetic response occur?

Back 88

preganglionic fibers may synapse on up to 30 postganglionic fibers

Front 89

Which cranial nerves does the PNS contain? sacral?

Back 89

cranial nerves III, VII, IX, and X
sacral at levels S2,3,4

Front 90

In the preganglionic parasympathetic nerves long or short? postganglionic PNS?

Back 90

long
short

Front 91

Is there a generalized PNS response?

Back 91

no, the pre to post ganglionic fibers is generally 1:1

Front 92

What NT is used for PNS at both terminals?

Back 92

acetylcholine

Front 93

What is pain over a given region of skin that is actually caused by disease from an internal organ?

Back 93

referred pian

Front 94

What is the theory that pain fibers from both internal organs and the body wall synapse on the same nerve (second order afferent) within the spinal cord?

Back 94

afferent nerve convergence
the brain has no mechanism of knowing whether the pain is from visceral or somatic rgion, most pains are from somatic regions, so the brain often perceives the pain as somatic pain