Unit 13 - Spinal Cord and Spinal Nerves

Question 1

The spinal cord may be subdivided into five regions, what are they

Answer 1

1. Cervical Region
2. Thoracic Region
3. Lumbar Region
4. Sacral Region
5. Coccygeal Region

Question 2

The spinal cord is ______ than the vertebral canal that houses it

Answer 2

Shorter

Question 3

The tapering inferior end of the spinal cord is called the ________

Answer 3

Conus medullaris

Question 4

marks the official “end” of the spinal cord proper (usually at the level of the ______)

Answer 4

Conus medullaris, first lumbar vertebra

Question 5

Inferior to the Conus Medullaris, groups of axons, collectively called the _______, project inferiorly from the spinal cord

Answer 5

Cauda equina

Question 6

Within the cauda equina is the _______, helps anchor the conus medullaris to the coccyx

Answer 6

Filum terminale

Question 7

The Filum Terminale is a thin strand of ________, helps anchor the conus medullaris to the coccyx

Answer 7

Pia Mater

Question 8

Located in the inferior cervical region of the spinal cord, contains the neurons that innervate the upper limbs

Answer 8

Cervical enlargement

Question 9

Extends through the mid-lumbar region of the spinal

cord and innervates the lower limbs

Answer 9

Lumbosacral enlargement

Question 10

The spinal cord is associated with _____ pairs of spinal nerves that connect the CNS to muscles, receptors, and glands

Answer 10

31

Question 11

The spinal cord regions that control the _______ are

larger because more neuron cell bodies are located there, and more space is occupied by the axons and dendrites.

Answer 11

Upper and lower limbs

Question 12

Each side of the spinal cord contains:

(a) ___ cervical nerves (C1-C8)
(b) ____ thoracic nerves (T1-T12)
(c) ____ lumbar nerves (L1-L5)
(d) _____ sacral nerves (S1-S5)
(e) ____ coccygeal nerves (Co)

Answer 12

8 - Cervical
12 - Thoracic
5 - Lumbar
5 - Sacral
1 - Coccygeal

Question 13

Lies between the dura mater and the inner walls of the vertebra, and houses loose connective tissue, blood vessels, and adipose connective tissue

Answer 13

Epidural Space

Question 14

A local anesthetic can be injected into the _____ of a pregnant female prior to delivery to deaden sensation from the waist down

Answer 14

Epidural space

Question 15

Some persons believe this type of obstetrical anesthesia is overused and is associated with increased risk to mother and child.

Answer 15

Epidural Space Spine Injection

Question 16

Although the cranial dura mater has an outer periosteal layer and an inner meningeal layer, the spinal dura mater consists of

Answer 16

Just one layer

Question 17

At each intervertebral foramen, the _____ extends between adjacent vertebrae and fuses with connective
tissue layers that surround the spinal nerves

Answer 17

Dura

Question 18

Deep to the dura mater and “subdural space” (which is only a potential space)

What’s deep to that?

Answer 18

Arachnoid

the subarachnoid space, which is a real space, filled with “cerebrospinal fluid”
(CSF).

Question 19

The clinical procedure for obtaining CSF is known as
a
(obtains about 3 to 9 milliliters of CSF)

Answer 19

lumbar puncture (commonly referred to as a spinal tap)

Question 20

A lumbar puncture must be performed inferior to this level to ensure the spinal cord is not pierced by the needle

Answer 20

at the level of the L1 vertebra

Question 21

A lumbar puncture typically is made at the level of either the ______

Answer 21

L3 and L4 vertebrae or the L4 and L5 vertebrae

To locate this level, the physician palpates the highest points of the iliac crests, which are at the same horizontal level as the spinous process of the L4 vertebra. The physician can then insert the lumbar puncture needle either directly above or directly below the spinous process of L4 when the vertebral column is flexed.

Question 22

Deep to the subarachnoid space, is a delicate, innermost meningeal layer composed of elastic and collagen fibers

Answer 22

Pia Mater

Question 23

This meninx directly adheres to the spinal cord and supports some of the blood vessels supplying the spinal cord

Answer 23

Pia Mater

Question 24

The spinal cord is partitioned into an inner _____ region and an outer _____ region

Answer 24

Gray Matter, White Matter

Question 25

The peripheral white matter (composed primarily of myelinated axons) provides a means of neural communication to and from _____

Answer 25

The Brain

Question 26

_________, of the spinal cord, conduct impulses from the peripheral sensory receptors of the body to the brain.

Answer 26

Ascending tracts

Question 27

_________, of the spinal cord, conduct motor impulses from the brain to the muscles and glands.

Answer 27

Descending tracts

Question 28

``` The ________ (which is dominated by dendrites and cell bodies of neurons and glial cells and unmyelinated axons) serves as a center for spinal reflexes. ```

Answer 28

Central gray matter

Question 29

There is a _______ in the center of the butterfly-shaped gray mater that is filled with cerebrospinal fluid.

Answer 29

central canal

Question 30

The _______ is continuous with the medulla oblongata and the ventricles of the brain.

Answer 30

central canal

Question 31

all spinal nerves are _____ nerves

Answer 31

mixed

Question 32

Each spinal nerve exits the vertebral canal and travels through an ______ above or below the vertebra of the same number.

Answer 32

intervertebral foramen

Question 33

a. The second cervical spinal nerve exits the vertebral canal through the intervertebral foramen between the C1 and the C2 vertebrae b. The eighth cervical spinal nerve leaves the intervertebral foramen between the C7 and T1 vertebrae. c. The spinal nerves inferior to the C8 spinal nerve exit below the vertebra of the same number. 1) For example, the second thoracic spinal nerve exits the vertebral canal through the intervertebral foramen between the T2 and T3 vertebrae.

Answer 33

True

Question 34

a specific segment of skin | supplied by a single spinal nerve.

Answer 34

“dermatome”

Question 35

All spinal nerves except for _____ innervate a segment of skin, so each of these nerves is associated with a dermatome. Thus, the skin of the body may be divided into sensory segments that collectively make up a dermatome map

Answer 35

C1

Question 36

a reactivation of their childhood chickenpox infection, a condition termed

Answer 36

Shingles

Question 37

What can trigger the development of shingles?

Answer 37

Psychological stress, other infections (such as a cold or the flu), and even a sunburn

Question 38

Dermatomes are also involved in ______, a phenomenon in which pain or discomfort from one organ is mistakenly referred to a dermatome Ex: Left arm pain during Heart Attack

Answer 38

“referred visceral pain” Some common sites of referred pain are useful in medical diagnosis

Question 39

a network of interweaving spinal nerves

Answer 39

Nerve Plexus

Question 40

Most of the thoracic spinal nerves ____, as well as nerves _____, do not form plexuses

Answer 40

(T2-T12), S5-Co1

Question 41

The left and right “cervical plexuses” are located deep on each side of the neck, immediately lateral to cervical vertebrae ________

Answer 41

C1-C4 These plexuses are formed primarily by spinal nerves C1-C4. The fifth cervical spinal nerve is not considered part of the cervical plexus, although it contributes some axons to one of the plexus branches

Question 42

One important branch of the cervical plexus is the _____, which is formed primarily from the C4 nerve and some contributing axons from C3 and C5

Answer 42

Phrenic Nerve

Question 43

The phrenic nerve travels through the _____ to innervate the diaphragm.

Answer 43

Thoracic Cavity

Question 44

How are Hiccups (“singultus”) caused?

Answer 44

by irritation to the phrenic nerve causing spasmodic contractions of the diaphragm. This movement, in turn, causes the epiglottis to close suddenly and make the characteristic sound of hiccups

Question 45

Networks of nerves that supply the upper limb.

Answer 45

The left and right “brachial plexuses”

Question 46

Each brachial plexus is formed by spinal nerves ______

Answer 46

C5-T1 The components of the brachial plexus extend laterally from the neck, pass superior to the first rib, and then continue into the axilla Each brachial plexus innervates the pectoral girdle and the entire upper limb of one side.

Question 47

Five major named nerves arise from the brachial plexus

Answer 47

1. The “axillary nerve” - innervates both the deltoid and the teres minor muscles. It receives sensory information from the superolateral part of the arm and skin 2. The “median nerve” - travels along the midline of the arm and forearm and deep to the carpal tunnel of the wrist. It innervates most of the anterior forearm muscles and several muscles in the palm. It receives sensory information from the palmar side of fingers #1, #2, #3, and the lateral one-half of finger #4 and from the dorsal tips of these same fingers. 3. The “musculocutaneous nerve” - innervates the biceps brachii and several other anterior arm muscles. It also receives sensory input from the lateral surface of the forearm. 4. The “radial nerve” - travels along the posterior side of the arm and then along the radial side of the forearm. The radial nerve innervates the triceps brachii and several other muscles on the posterior of the forearm. It receives sensory information from the posterior arm and forearm surface and the dorsolateral side of the hand. 5. The “ulnar nerve” - descends along the medial side of the arm. It wraps posterior to the medial epicondyle of the humerus and then runs along the ulnar side of the forearm. It innervates some of the anterior forearm muscles and many of the muscles in the palm. It receives sensations from the skin of the dorsal and palmar aspects of fingers #5, and the medial half of finger #4.

Question 48

can be compressed within the axilla, or it can be damaged if the surgical neck of the humerus is broken

Answer 48

Axillary Nerve Injury

Question 49

when this is damaged has great difficulty abducting the arm due to paralysis of the deltoid muscle, as well as anesthesia (lack of sensation) along the superolateral skin of the arm.

Answer 49

Axillary Nerve

Question 50

subject to injury during humeral shaft fractures or in injuries to the lateral elbow

Answer 50

Radial Nerve Injury

Question 51

results in paralysis of the extensor muscles of the forearm, wrist, and fingers

Answer 51

Radial Nerve Injury

Question 52

A common clinical sign of radial nerve injury is ______, meaning that the patient is unable to extend his or her wrist

Answer 52

wrist drop

Question 53

The patient also experiences anesthesia along the posterior arm, the forearm, and the part of the hand normally supplied by this nerve.

Answer 53

Radial Nerve Injury

Question 54

One cause of this is improper use of crutches, a condition called ______

Answer 54

Posterior Cord Injury, Crutch Palsy

Question 55

may be impinged on or compressed as a result of carpal tunnel syndrome because of the close confines of this narrow passage

Answer 55

Median Nerve

Question 56

the nerve may be injured by any deep laceration of the wrist

Answer 56

Median Nerve

Question 57

often results in paralysis of the thenar (thumb muscles) group of muscles

Answer 57

Median Nerve Injury

Question 58

The classic sign of median nerve injury is the ________, which develops over time as the thenar eminence wastes away until the hand eventually resembles that of an ape (apes lack well-developed thumb muscles).

Answer 58

ape hand deformity

Question 59

The lateral two lumbricals are also paralyzed, and sensation is lost in the part of the hand supplied by the median nerve.

Answer 59

Median Nerve Injury

Question 60

may be injured by fractures or dislocations of the elbow because of this nerve’s close proximity to the medial epicondyle of the humerus

Answer 60

Ulnar Nerve

Question 61

When you “hit your funny bone,” you have actually hit your _____

Answer 61

Ulnar Nerve

Question 62

Most of the intrinsic hand muscles are paralyzed (including the interossei muscles, the hypothenar muscles, the adductor pollicis, and the medial two lumbricals), so the person is unable to adduct or abduct the fingers.

Answer 62

Ulnar Nerve Injury

Question 63

the person experiences sensory loss along the medial side of the hand

Answer 63

Ulnar Nerve Injury

Question 64

A clinician can test for ______ by having a patient hold a piece of paper tightly between the fingers as the doctor tries to pull it away. If the person has weak interossei muscles, the paper can be easily extracted.

Answer 64

ulnar nerve injury

Question 65

A superior trunk injury affects the ______

Answer 65

C5 and C6 anterior rami

Question 66

can be injured if the arm is excessively abducted, as when a neonate’s arm is pulled too hard during delivery

Answer 66

The inferior trunk of the brachial plexus

Question 67

also may happen when grasping something above the head to break a fall—for example, grabbing a branch to keep from falling out of a tree

Answer 67

Inferior trunk injuries

Question 68

The left and right ______ are formed by spinal nerves L1-L4 located lateral to the L1-L4 vertebrae

Answer 68

“lumbar plexuses”

Question 69

Which spinal nerves from the lumbar plexuses

Answer 69

L1-L4

Question 70

Which spinal nerves form the brachial plexuses

Answer 70

C5-T1

Question 71

Which spinal nerves form the cervical plexuses

Answer 71

C1-C4

Question 72

What forms phrenic nerve

Answer 72

C4 nerve and some contributing axons from C3 and C5

Question 73

There are two principal named nerves that arise from the lumbar plexus, what are they

Answer 73

Femoral Nerve & Obturator Nerve

Question 74

The “femoral nerve” innervates what

Answer 74

the quadriceps femoris, the sartorius, and a hip | muscle

Question 75

The femoral nerve receives sensory information from where?

Answer 75

from the anterior and inferomedial | thigh as well as the medial aspect of the leg

Question 76

What innervates the gracilis and several other thigh muscles

Answer 76

Obturator Nerve

Question 77

Obturator Nerve receives sensory information from where

Answer 77

the superomedial skin of the thigh

Question 78

Formed from spinal nerves L4-S4 and are | located immediately inferior to the lumbar plexuses

Answer 78

The left and right “sacral plexuses”

Question 79

The Sacral Plexuses are formed from what

Answer 79

spinal nerves L4-S4

Question 80

There are two principal nerves that arise from the sacral plexus, what are they

Answer 80

Sciatic Nerve - Composed of two nerves wrapped in a connective tissue sheath (Tibial Nerve & Common Fibular Nerve)

Question 81

It passes deep to the gluteus maximus and piriformis muscles

Answer 81

Sciatic Nerve

Question 82

Just superior to the ______ the sciatic nerve splits into the tibial nerve and the common fibular nerve

Answer 82

popliteal fossa

Question 83

The “tibial nerve” innervates what

Answer 83

the hamstrings, gastrocnemius, soleus, and several | other muscles.

Question 84

Tibial Nerve receives sensory info from what

Answer 84

receives sensory impulses from the skin covering the sole (plantar surface) of the foot

Question 85

The “common fibular nerve” (“common peroneal nerve”) branches to innervate what

Answer 85

the peroneus longus (fibularis longus), tibialis anterior, and several other muscles of the leg and foot.

Question 86

Common Fibular Nerve receives sensory information from where

Answer 86

from the anterolateral part of the leg, the toes, and the dorsal surface of the foot

Question 87

Injury to the sciatic nerve produces a condition known as ________, which is characterized by extreme pain down the posterior thigh and leg

Answer 87

sciatica

Question 88

may be injured due to fracture of the neck of the fibula or compression from a leg cast that is too tight

Answer 88

Common Fibular Nerve

Question 89

One classic sign of fibular nerve injury is _____, As a person lifts the affected foot to take a step, the lack of innervation of the anterior and lateral leg muscles causes the foot to fall into the plantarflexed position

Answer 89

Foot Drop

Question 90

The hollow “neural canal” in the embryonic neural tube develops into the ______

Answer 90

the central canal of the spinal cord the neural canal doesn’t “shrink” in size; rather the neural tube walls grow and expand.

Question 91

A newborn’s spinal cord extends to about the level of

Answer 91

L3

Question 92

A child’s spinal cord may extend to the level of

Answer 92

L2

Question 93

An adult’s spinal cord typically terminates at the level of

Answer 93

L1

Question 94

Trauma to the spinal cord above ____ typically leads to death by asphyxiation because innervation to the intercostal muscles and innervation to the diaphragm is lost

Answer 94

C3

Question 95

paralysis of all four limbs

Answer 95

Quadriplegia

Question 96

Trauma between _____ also typically results in “quadriplegia”.

Answer 96

C4 and C7 If spinal nerves C3 and C4 are intact, the person will still have a functioning phrenic nerve and be able to breathe with just their diaphragm and not be dependent upon a mechanical respirator.

Question 97

Trauma to the spinal cord between T1 and L1 may lead to _____

Answer 97

paraplegia which is paralysis of both lower extremities and, generally, the lower trunk.

Question 98

What leads to paraplegia

Answer 98

trauma to the spinal cord between T1 and L1