Peripheral Nerve Elements

Question 1

___________ neurons (aka somatosensory) and ____________ neurons (aka motor) are the key components of a peripheral nerve when considering regional blockade.

Answer 1

afferent

efferent

Question 2

The peripheral nerve will have all 3 types fibers

Answer 2

afferent
efferent
autonomic

Question 3

____________ nerves travel in the intercostal spaces and to the thoracic and abdominal compartments and are called _______________________.

Answer 3

Spinal

intercostal nerves

Question 4

Spinal nerves travel in the intercostal spaces and to the thoracic and abdominal compartments and are called intercostal nerves.

Question 5

peripheral nerve physical size (greatest to least)

Answer 5

Peripheral nerve >afferent and efferent fibers> fascicles (bundles of axons/ motor or dendrites/ sensory) > individual nerve fibers (aka axons)

Question 6

From the spinal cord, spinal nerves are by anatomy ________________________ because they exist outside the CNS and function in their three major roles as noted below

Answer 6

peripheral nerves

Question 7

The functional unit is the _________ with the axon being the _______________ portion.

Answer 7

neuron

conduction

Question 8

________________ are interspersed among the axon at spaces that are not myelinated

Answer 8

Nodes of Ranvier

*These nodes, or axon intervals, have voltage gated sodium channels that propagate the nerve conduction and are a primary site for local anesthetic action.

Question 9

Another description of the neurons is as follows

Answer 9

Cell body (soma)- branches of dendrites that are receivers – the axon for sending

Question 10

________________ surround the axon, produce myelin that wraps the nerve and accelerates nerve conduction

Answer 10

schwann cells

Question 11

There are three states of the sodium channel:

Answer 11

activated open, inactivated closed, rested closed

*Local anesthetics have the ability to block the channels in the first two states only.

Question 12

3 layers of the nerve in the periphery correspond with the ________________ of the CNS

Answer 12

meninge layers

Question 13

In the PNS, the layers are the

Answer 13

Epineurium, (outermost)
Perineurium, (middle)
Endoneurium (innermost)

Question 14

which layer binds the substances together into bundles?

Answer 14

epineurium

Question 15

which layer binds individual fasciles protecting the nerves with collagen and connective tissue?

Answer 15

perineurium

Question 16

which layer consists of fluid and fibrous tissue that is produced in part by Schwann cells?

Answer 16

endoneurium

Question 17

myelinated fibers

Answer 17

larger
faster
motor and sensory function

Question 18

unmyelinated fibers

Answer 18

slower
smaller
transmit pain, temperature, and autonomic impulses

Question 19

A_Beta fibers functionality includes

Answer 19

motor, touch, and pressure recognition

Question 20

A_Alpha fibers functionality includes

Answer 20

motor signals and proprioception

Question 21

B fibers have less _________________ and carry ______________ signals

Answer 21

myelination

autonomic

Question 22

A_Delta fibers transmit

Answer 22

pain and temperature

Question 23

A_Gamma fibers carry

Answer 23

reflexes

Question 24

With local anesthetics, the ________ and more ______________ fibers are generally harder to block

Answer 24

larger

myelinated

Question 25

C fibers carry

Answer 25

pain and temperature signals *smallest fibers and unmyelinated

Question 26

CNS communication to the body occurs through the _____________________ from the ventrolateral aspect of the cord

Answer 26

ventral root

Question 27

order of blockade generally

Answer 27

B fibers, C fibers, A delta fibers followed by the heavily myelinated fibers like A alpha. *As far as recovery from the effect of the local anesthetic, the “wearing off” occurs in the reverse order.

Question 28

Spinal nerve components

Answer 28

31pairs 8 cervical (lying above the like named vertebral body, except 8th) 12 thoracic (lying below the respective vertebral body) 5 lumbar 5 sacral 1 coccygeal nerve (all lying below the vertebral body. )

Question 29

CNS communication from the body (sensory) is through the

Answer 29

dorsolateral aspect of the cord

Question 30

vertebral bone components

Answer 30

33 Levels 7 Cervical, 12 Thoracic, 5 Lumbar, 5 Sacral, 4 coccyx)

Question 31

Spinous processes are directed caudad at the cervical levels while straight at the lumbar

Answer 31

caudad

Question 32

__________ is the most prominent cervical level called “vertebral prominens")

Answer 32

C7

Question 33

__________correlates with the cricoid cartilage

Answer 33

C6

Question 34

___________ correlates with the superior angle of the scapula and sternal notch

Answer 34

T2

Question 35

_____ is the plane of Ludwig that correlates carina and angle of Louis

Answer 35

T4

Question 36

______ is the inferior angle of the scapulae

Answer 36

T7

Question 37

_____ is the Xiphoid

Answer 37

T9

Question 38

The umbilicus correlates with the level of ______

Answer 38

T10

Question 39

________ correlates with the superior iliac crest

Answer 39

L4

Question 40

________ is an area of SKIN, that is the surface, sensory identifier for nerve delineation *These layers have overlap which can explain the injury to a given nerve with preserved sensation

Answer 40

dermatome

Question 41

_______ correlates with the superior iliac crest

Answer 41

L4

Question 42

____________ are the associative nerves controlling muscles such as C6 flexing at the elbow

Answer 42

myotomes

Question 43

_____________ are the bone and joint nerve associations

Answer 43

Osteotomes

Question 44

Cervical plexus is formed by

Answer 44

C1-C4

Question 45

Brachial plexus is formed by _______ between the anterior and middle scalene muscles

Answer 45

C5-T1

Question 46

Lumbar plexus is ______.

Answer 46

T12-L4

Question 47

Femoral nerve develops from __________.

Answer 47

L2-L4

Question 48

The lateral femoral cutaneous is of special interest since it innervates the hip and lateral thigh. It originates from ________

Answer 48

L2, 3

Question 49

Sacral plexus is _________

Answer 49

L4-S4

Question 50

Sciatic nerve is formed from tibial _______ and common peroneal nerves (______).

Answer 50

L4-S3 L4-S2

Question 51

_______ nerve- signals the diaphragm for respiratory control, derived from _________

Answer 51

Phrenic C3, 4, 5

Question 52

_______ nerve. ________Functionally operates the triceps, supination of the forearm, extension of the wrist, abduction of thumb and extension of other fingers.

Answer 52

Radial C5-T1

Question 53

_________ nerve follows the track of the brachial artery lying medially to it. Originating at _________. Functionally, it flexes the elbow, pronates the forearm, flexes the wrist, flexes the fingers and thumb, abducts the thumb

Answer 53

Median C5, 6, 7

Question 54

______nerve is formed from ________. It follows the brachial artery following the posterior aspect of the medial epicondyle. Flexion of wrist, ring and small fingers, adduction of fingers, adduction of thumb, flexion of thumb.

Answer 54

Ulnar C8-T1

Question 55

_______________. Passes through the axilla into the shoulder.

Answer 55

Axillary Nerve C5-6

Question 56

________________________ Innervates the coracobrachialis and biceps before innervating the forearm as the lateral antebrachial cutaneous nerve.

Answer 56

Musculocutaneous Nerve C 5,6,7