Ga060802

Front 1

Why spinal cord important?

Back 1

1. Diagnostic Prodcedures
2. Therapeutic Procedures
3. Referred Pain
4. Vascular system

Front 2

Central Nervous System

Back 2

Brain and spinal cord-both continuous with the foramen magnum at the base of skull

Front 3

Peripheral Nervous System

Back 3

12pairs of cranial nerves + 31 pairs of spinal nerves

Front 4

Somatic Nervous System
1. Definition
2. Composition

Back 4

1. Part of the nervous system that controls and supplies the body (other than internal organs)
2. Contains both sensory & motor components

Front 5

Visceral Nervous System
1. Definition
2. How info conveyed

Back 5

1. Part of nervous system that controls internal organs
2. Sensory fibers convey info to the CNS to the brain and then motor back to the body

Front 6

Neuron
1. Definition
2. Structure

Back 6

1. Structural & function unit of nervous system
2. Contains body(soma), one or more dendrites (conduct impulses TO body), a single axon (conduct impulses FROM body).

Front 7

Synapse
1. Definition

Back 7

1. Junction where one neuron ends on another neuron.

Front 8

Example of Chemical Synapse

Back 8

1. pre-synaptic neuron releases a chemical neurotransmitter into synaptic cleft
2. that substance will bind to a receptor molecule on the post-synaptic neuron
3. the post-synaptic membrane will be either excited or inhibited

Front 9

Myelin Sheath
1. Purpose
2. Appearance

Back 9

1. Myelin is a lipoprotein substance that forms a sheath around some axons which acts to increase conduction veloctiy.
2. Imparts whitish color.

Front 10

Explain difference in lengths of spinal cord vs. verterbral column

Back 10

1. Spinal cord is shorter than vertebral column - ends btwn L1 & L2.
2. During development, growth of cord not maintained relative to vertebral column--progressive shortening

Front 11

Conus medullaris

Back 11

The end of the spinal cord (~L1-L2)

Front 12

Spinal cord segment

Back 12

Area of the spinal cord where the nerves attach.

Front 13

Account for different types of spinal nerves

Back 13

1. 8 Cervical
2. 12 Thoracic
3. 5 Lumbar
4. 5 Sacral
5. 1 Coccyxgeal

Front 14

How are the nerves named (based on column segment)?

Back 14

Cervical (Special): Nerve emerges superior to respective vertebra
(8th nerve btwn C7 & T1)
All other: nerves emerge below respective vertebra
NOTE: lumbar/sacral/coccygeal nerves are longer & more oblique due to end of spinal cord ~L1 & L2

Front 15

Cauda Equina

Back 15

Leash like bundle of fibers of lumbar/sacral/coccygeal to get to their foramina to exit
(horse's tail)

Front 16

Filum terminale internum

Back 16

Delicate filament of non-nervous tissue made of pia mater

Front 17

Filum terminale externum

Back 17

Filum terminal internum called this after exits dural sac (~S2). Goes down along sacrum, then exits sacral hiatus and binds to coccyx.

Front 18

Two enlargements of the spinal cord

Back 18

Enlarged b/c these are areas of cord to which spinal nerves innervating either upper/lower limbs attach.
1. Cervical enlargement (C4-T1)

Front 19

Gray Matter

Back 19

1. 'H' shaped in cross section
2. Made up of cell bodies

Front 20

White Matter

Back 20

1. Made up of myelinated axons that surround gray matter
2. Either ascend to brain or descend from brain to cord.

Front 21

Gray matter "structures"

Back 21

1. Ventral horn
2. Dorsal horn

Front 22

Ventral Horn

Dorsal Horn

Back 22

1. Contains motor neurons that supply skeletal muscle of body
2. Contains sensory neurons that receive impulses from spinal nerves sensory info

Front 23

What is different about T1-L2?

What is its function?

Back 23

1. Additional horn: Lateral horn
2. Contains cell bodies of the Autonomic Nervous System
3. These neurons supply(involuntary): cardiac muscle, smooth muscle & glands

Front 24

Describe the typical structure of a spinal nerve.

Back 24

1. Dorsal & ventral root which attach to cord by "rootlets". Dorsal root has spinal ganglion (DRG).
2. Two roots unite to form spinal nerve = mixed signal (sensory & motor)
3. Spinal nerve exits intervertebral foramen and divides into branches/rami = dorsal and ventral ramus
(NOTE: since spinal nerve is mixed, so are both dorsal & ventral rami.

Front 25

Dorsal roots

Ventral roots

Back 25

1. Sensory conveying info INTO cord
2. Motor carrying impulses AWAY from cord

Front 26

Ganglion

Sympathetic Ganglion

Back 26

1. Collection of neurons outside of the CNS.
2. A cluster of nuerons outside the CNS, but different from DRG.

Front 27

Gray & White Rami Communicantes
1. Definition
Exceptions

Back 27

1. Connects the ventral ramus of the spinal nerve to the sympathetic ganglion from T1-L2
2. If above T1, contains only gray ramus
2b. If below L2, contains only gray ramus

Front 28

Two types of Ganglia

Back 28

1. sensory (dorsal)
2. autonomic (ventral)

Front 29

Autonomic Ganglia

Back 29

1. All autonomic ganglia (whether sympathetic or parasympathetic are MOTOR ganglia)
2. Therefore, all of these are motor neurons carrying impulses to cardiac muscle, smooth muscle, glands
3. All autonomic ganglia have a synapse in them

Front 30

Dorsal Ramus

Back 30

1. Mixed
2. Motor fibers supply erector spinae and a branch will continue to supply skin of back

Front 31

Ventral Ramus
1. Innervation?

Back 31

1. Everything except deep back muscles and skin of back
2. Supplies muscles in body walls (intercostal muscles), skin by either lateral cutaneous branch or anterior cutaneous branch
(anterior body wall)-ventral ramus
3. Innervates limbs also

Front 32

Brachial Plexus
1. Composition
2. Innervation

Back 32

1. Lower cervical nerves and upper thoracic nerves
2. Branches of this supply motor & sensory innervations to entire limb

Front 33

Lower limb innervated by what?

Back 33

Lumbar & sacral plexuses

Front 34

To devuse scheme of functional components of nerves, what 3 questions need to be asked?

Back 34

1. Is the nerve fiber sensory/afferent (convey impulse from body to CNS) or motor/efferent (convey impulse from CNS to body)?
2. Is it somatic (going to outer part of body wall) or visceral (internal organs)?
3. Is it general or special? (general nerve fibers distribute to tissue or structures with a relatively wide distribution in the body)

Front 35

Example of Scheme:
What would a sensory fiber from the skin be classified as?

Back 35

skin-General, Somatic, Afferent

Front 36

How many possible functional components?
Where do they occur-cranial vs. spinal?

Back 36

7 (SSE doesn't exist)
NOTE: special components occur in most cranial nerves. General components occur in most cranial nerves and in all spinal nerves; all spinal nerves have all four general compomnents and only general components

Front 37

What are GVE Fibers?

What happens if they are sympathetic?

Back 37

1. Autonomic nervous system (pre/post synaptic)
2. Pre-synaptic neurons lie in lateral horn & axon leaves through ventral root into spinal nerve; goes down white ramus communicantes where it synapses on post-synaptic neuron; then goes out gray ramus back to spinal nerve and either follow dorsal or venntral depending on location of innervation

Front 38

What about GVA Fibers?

GSA?

Back 38

1. They follow GVE's that go to internal organs and their cell bodies lie in dorsal root ganglion.
2. Have cells in DRG

Front 39

In typical spinal nerve, T1-L2, dorsal roots are...
ventral roots are...

Back 39

1. Dorsal roots are entirely sensory = GSA, GVA
2. Ventral roots are entirely motor = GSE, GVE

Front 40

Where do pre-synaptic GVEs travel?

Where do post-synaptic GVEs travel?

Back 40

1. White rami

2. Gray rami

Front 41

Dermatomes

Back 41

Strips of skin that are innervated by a single pair of spinal nerves

Front 42

Referred Pain

Landmark: T10 dermatome

Back 42

T10 dermotome supplied by T10 spinal nerve includes skin around umbilicis (people who have appendicitus feel pain here since Afferent/sensory fibers in appendix end in T10 spinal cord segment, in dorsal horn; CNS misinterprets where pain is coming from.

Front 43

What are limbs innervated by?

What is a nerve plexus?

Back 43

1. Ventral rami but through plexuses.

2. Where ventral rami of adjacent spinal nerves comine and redivide.

Note: Fibers leave cord in one spinal nerve are going to redistribute through mulitiple branches of the plexus.

Front 44

Comparison of dermatomal map vs. sensory distribution of peripheral nerve map.

Back 44

Two different maps except in the thoracic region where there is no plexus formation and the thoracic nerves remain un-united and the strips of skin are the same.

Front 45

Three spinal arteries
1. Type
2. Where originate?
3. Size

Back 45

1. anterior spinal artery
1b. 2 posterior spinal arteries
2. They branch off veterbral arteries in the skull and then run down on spinal cord - either along ventral median fissure or posteriolaterally (for posterior arteries).
3. Spinal arteries are small with insufficient blood supply, so segmental arteries must anastamose (join) spinal arteries to supply enough blood.

Front 46

Segmental medullary arteries

Back 46

Segmental arteries that anastamose (join) spinal arteries to supply enough blood to spinal cord.

Front 47

Origin:
Cervical region
Thoracic region
Lumbar region

Back 47

1. Verterbral arteries
2. Intercostal arteries
3. Lumbar arteries

Front 48

Great Anterior Medullary Segmental Artery/Artery of Adamkiewicz

Why is it important?

Back 48

1. Segmental medullary artery that is especially large, springs off theleft side and usualy comes from a lower intercostal artery - in this case, the lumbar artery.
2. This segment supplies the lumbral-sacral enlargement of teh spinal cord.
NOTE: if this artery is occluded, lower part of spinal cord will lose its blood supply and person will likely become paraplegic.

Front 49

What are the layers of meninges?

Back 49

1. Epidural space
2.Dura Mater (potential)
3. Arachnoid Mater
4. Subarachnoid space - CSF here (real)\
5. Pia mater

Front 50

Dura Mater
Arachnoid Mater
Pia Mater

Back 50

1. Very tough fibrous coat that surrounds outermost covering of cord
2. Delicate spider-web like layer that lies just inside dura
3. Vascular membrane that adheres so closely to cord that it is impossible to separate from cord.

Front 51

Denticulate ligament

Useful landmark for?

Back 51

1. Pia mater extends bilaterally from cord as toothed processess that attach to the inner surface of the dura.
2. Holds spinal cord in place and anchors it to dura.
3. Separates dorsal rootlets from ventral rootlets of spinal nerve. (Dorsal on top)

Front 52

Where does the sac of dura mater and arachnoid end

Back 52

S2 vertebral level, below which is the dural part of the filum terminale which exits sacral hiatus & attaches to coccyx.

Front 53

Spaces Related to Meninges

Back 53

1. Subarachnoid space: between arachnoid and pia mater = real space of CSF (protects spinal cord and brain)
2. Subdural space = narrow potential space (blood could enter)
3. Epidural space = btwn dura mater and periosteum lining of vertebral canal. (contains fat, connective tissue, plexus of veins) = Batson's plexus

Front 54

Batson's plexus

Back 54

1. Internal vertebral venous plexus in epidural space
2. Drains the vertebral column and is drained by intervertebral veins which exit through the intervertebral foramina.

Front 55

What unique quality is there about Batson's plexus and intervertebral veins?

Back 55

1. Valve-less
2. Clinically provides a pathway for infection or cancer to spread.

Front 56

Lumbar cistern

Back 56

1. Area entered during a lumbra puncture (into the subarachnoid space) btwn L2 and S2

Front 57

Supracristal plane

Back 57

1. Plane cuts across the upper border of iliac crests which lies at L4 verterbral level--place to insert needle above or below

Front 58

Laminectomy

Back 58

Remove laminae of spine via chisel and hammer--removes spine and adjacent parts of laminae--> exposes cord and meninges.