Spinal Cord and Spinal Nerves

Question 1

the spinal cord is a two way or one way conduction system?

Answer 1

two way

Question 2

what is the spinal cord?

Answer 2

flattened tubular structure located within the vertebral canal and extends from medulla oblongata to approximately L1

Question 3

where does the spinal cord extend in newborns?

Answer 3

it extends to L4 in newborn and the vertebral column grows faster than the spinal cord

Question 4

what is the significance of the cervical and lumbar enlargements?

Answer 4

they provide peripheral nerves for extremities like the arm, forearm, thigh and leg

Question 5

what are the two structures you can find at the terminal end of the spinal cord?

Answer 5

conus medullaris and the film terminale

Question 6

what is the conus medullaris?

Answer 6

tapering end of spinal cord

Question 7

what is the filum terminale?

Answer 7

tissue (actually pia mater) than extends inferiorly to anchor spinal cord to coccyx, part of covering for spinal cord

Question 8

what are the meninges?

Answer 8

connective tissue coverings that surround brain and spinal

Question 9

what are the layers of the meninges?

Answer 9

dura mater
arachnoid mater
pia mater

Question 10

what is the dura mater?

Answer 10

the fibrous outer layer

Question 11

what is the arachnoid mater?

Answer 11

middle later

Question 12

what is the pia mater?

Answer 12

thin transparent layer that adheres to brain and spinal cord

Question 13

where do we find the epidural space?

Answer 13

between dura and vertebral canal

Question 14

where can we find the subarachnoid space?

Answer 14

formed by deep spider-like extensions of arachnoid&raquo_space; contains cerebral spinal fluid&raquo_space; protective layer around brain and spinal cord

Question 15

what does the arachnoid space push against?

Answer 15

its pushed tight against the dura mater

Question 16

what is the pia mater?

Answer 16

thin transparent layer that adheres to brain and spinal cord

Question 17

what is an important structure we can find within the pia mater?

Answer 17

denticulate ligaments

Question 18

what is the denticulate ligaments?

Answer 18

small-toothed, triangular extensions of pia that attach to arachnoid/dura mater&raquo_space; suspend spinal cord in center of meningeal sac

Question 19

what kind of trauma can happen in the subdural space?

Answer 19

subdural hematoma

Question 20

what is the subdural space? example of trauma affecting this area?

Answer 20

artificial space created by separation of dura and arachnoid&raquo_space; typically caused by trauma and nervous tissue dysfunction; subdural hematoma

Question 21

what is meningitis?

Answer 21

inflammation of the meninges typically due to infection of the CSF

Question 22

what is a lumbar puncture?

Answer 22

procedure used to obtain needle access into subarachnoid space, you obtain cerebral spinal fluid, inject contrast dyes, test pressure, etc…

Question 23

where is the lumbar puncture performed in the back?

Answer 23

in the L3/L4 or L4/L5 intervertebral space, inferior to the conus medullaris, additionally we use the supracristal line that passes through L4 with the patient bent forward to open vertebrae and puncture more easily

Question 24

what is the epidural space? why is this significant

Answer 24

a network of large thin walled blood vessels called the epidural venous plexus embedded within fatty tissue and so you can inject anesthetic here

Question 25

what is the white matter?

Answer 25

composed of tracts of myelinated axons because of myelin

Question 26

how is the white matter subdivided?

Answer 26

anterior, lateral, and posterior white columns

Question 27

what are tracts?

Answer 27

bundles of nerve fibers with a common origin and destination that carry similar information

Question 28

what are the tracts divided into?

Answer 28

ascending and descending tracts

Question 29

the ascending tracts are always sensory or motor?

Answer 29

sensory

Question 30

the descending tract are always sensory or motor?

Answer 30

motor

Question 31

what is the gray matter?

Answer 31

forms central H-shape composed of unmyelinated axons plus motor and interneurons

Question 32

what is the gray matter divided into?

Answer 32

dorsal horn, ventral horn, lateral horn

Question 33

what is the dorsal horn divided into?

Answer 33

sensory functions

Question 34

what is the ventral horn divided into?

Answer 34

motor functions

Question 35

what is the lateral horn divided into?

Answer 35

only found in the thoracic region - autonomic/sympathetic function

Question 36

what are spinal roots?

Answer 36

these emerge from the spinal cord at each vertebral level

Question 37

what are the spinal roots divided into?

Answer 37

dorsal and ventral roots

Question 38

what are the dorsal roots; what important structure can we also note associated with the dorsal roots?

Answer 38

contain predominantly afferent fibers (sensory); contain cell bodies of primary sensory neurons

Question 39

what are the ventral roots?

Answer 39

contain efferent fibers (motor)

Question 40

what do the ventral and dorsal roots fuse to form?

Answer 40

spinal nerves

Question 41

how can we classify spinal nerves?

Answer 41

mixed

Question 42

where do the ventral and dorsal roots fuse?

Answer 42

at the intervertebral foramen

Question 43

how do the roots travel?

Answer 43

inferiorly before exiting vertebral column since spinal cord does not reach inferior end of spinal canal

Question 44

the L2 - Co1 spinal roots inferior to conus medullaris on route to exit at proper intervertebral foramen are also known as?

Answer 44

cauda equina

Question 45

the caudal equina is meninges or nervous tissue?

Answer 45

nervous tissue

Question 46

the filum terminale is meninges or nervous tissue?

Answer 46

meninges

Question 47

where do the spinal nerves exit from c1-c7?

Answer 47

they exit superior to vertebrae for which they are named

Question 48

where do the spinal nerves exit for c8?

Answer 48

exit between c7 and T1

Question 49

where do the spinal nerves exit from T1-Co1?

Answer 49

they exit inferior to the vertebrae for which they are named

Question 50

what is the myotome?

Answer 50

all muscles supplied by a specific spinal nerve?

Question 51

with respect to myotomes, when you have muscles supplied by multiple spinal nerves what happens when you have loss of a spinal nerve?

Answer 51

it will result in muscle weakness

Question 52

what do myotomes help with in a clinical setting?

Answer 52

tests muscle strength and reflexes to determine what spinal nerves are affected or fine

Question 53

what are dermatomes?

Answer 53

area of skin that that provides sensory information via a single set of spinal nerves

Question 54

what is usually indicated if symptoms follow a dermatome (pain, loss of sensation or a rash)?

Answer 54

a pathology that involves the spinal nerve

Question 55

what is the result if there is dermatome overlap?

Answer 55

sensation would be lessened not lost