Chapter 13: Spinal Cord and Spinal Nerves

Question 1

Which of the three spinal meninges is the most superficial? a) Arachnoid mater b) Dura mater c) Meninx mater d) Pia mater e) Epi mater

Answer 1

b) Dura mater

Question 2

Which of the structures listed below contains cerebrospinal fluid? a) Epidural space b) Subarachnoid space c) Dural space d) Meninx e) Pia mater

Answer 2

Answer: b) Subarachnoid space

Question 3

Denticulate ligaments are thickenings of a) arachnoid mater. b) pia mater. c) dura mater. d) interstitial fluid. e) subdural space.

Answer 3

b) pia mater.

Question 4

What spinal cord feature is the area where the nerves that supply the lower limb emerge? a) Lumbar enlargement b) Filum terminale c) Cauda equina d) Cranial nerve XII e) Cervical enlargement

Answer 4

a) Lumbar enlargement

Question 5

Which of the following structures contains only sensory axons that conduct nerve impulses from sensory receptors in the skin, muscles and internal organs to the CNS? a) Spinal nerves b) Cauda equina c) Anterior root of spinal nerves d) Posterior root of spinal nerves e) Conus medullaris

Answer 5

d) Posterior root of spinal nerves

Question 6

Which layer of protective connective tissue is the outermost covering surrounding a spinal nerve? a) dura mater b) pia mater c) endoneurium d) perineurium e) epineurium

Answer 6

e) epineurium

Question 7

What type(s) of axons are wrapped in a protective endoneurium? 1. Myelinated 2. Unmyelinated 3. Only dendrites are surrounded by endoneurium a) 1 only b) 2 only c) 3 only d) Both 1 and 2 e) None of these choices

Answer 7

d) Both 1 and 2

Question 8

Spinal nerves 1. Are parts of PNS. 2. connect the CNS to sensors and effectors in all parts of the body. 3. are named according to the region of the cord from which they emerge. a) 1 only b) 2 only c) 3 only d) both 1 & 3 e) 1, 2 & 3

Answer 8

e) 1, 2 & 3

Question 9

Intercostal nerves a) are also known as cervical nerves. b) do not enter into a plexus and directly connect to the structures they supply. c) are found in the C6-T4 area of the vertebral column. d) extend through the sacrum. e) do not exist in humans.

Answer 9

b) do not enter into a plexus and directly connect to the structures they supply.

Question 10

A man presents with median nerve palsy in his left hand. What is the most likely site of injury? a) Dorsal scapular nerve b) Intercostal nerve c) Lumbar plexus d) Median nerve e) Radial nerve

Answer 10

d) Median nerve

Question 11

Which region of the spinal cord carries nerve impulses for proprioception? a) Posterior white column b) Anterior gray horn c) Anterior white column d) Lateral white column e) Dermatome tract

Answer 11

a) Posterior white column

Question 12

Which white matter tracts of the spinal cord carry sensory information? a) Ascending tracts b) Descending tracts c) Integration tracts d) Columnar tracts e) Epidural tracts

Answer 12

a) Ascending tracts

Question 13

Which type of descending motor pathway conveys nerve impulses that originate in the cerebral cortex and are destined to cause precise, voluntary movements of skeletal muscles? a) Indirect pathway b) Direct pathway c) Reflex arc d) Somatic arc e) Muscle spindle

Answer 13

b) Direct pathway

Question 14

Which type of descending motor pathway originates in the brainstem and governs automatic movements that help regulate muscle tone, posture and balance? a) Indirect pathway b) Direct pathway c) Reflex arc d) Somatic arc e) Muscle spindles

Answer 14

a) Indirect pathway

Question 15

Which of the following parts of a reflex arc monitors body conditions?

a) Sensory receptor
b) Integrating center
c) Motor neuron
d) Effector
e) Interneuron

Answer 15

a) Sensory receptor

Question 16

Which of the following parts of a reflex arc receives sensory information and decides how to respond to a change in the body’s condition?

a) Sensory receptor
b) Sensory neuron
c) Motor neuron
d) Effector
e) Integration center

Answer 16

e) Integration center

Question 17

Which of the following parts of a nervous reflex arc is usually a muscle or gland?

a) Sensory receptor
b) Sensory neuron
c) Motor neuron
d) Effector
e) Integration center

Answer 17

d) Effector

Question 18

Which of the following parts of a reflex arc would have a cell body in the posterior root ganglion?

a) Sensory receptor cell
b) Sensory neuron
c) Motor neuron
d) Effector
e) Interneuron

Answer 18

b) Sensory neuron

Question 19

A nerve impulse initiated at a muscle spindle has to travel through which of the following structures to get into the spinal column?

a) Anterior root of spinal nerve
b) Posterior root of spinal nerve
c) Tectospinal tract
d) Central canal
e) Lateral reticulospinal tract

Answer 19

b) Posterior root of spinal nerve

Question 20

In response to a muscle being stretched, a muscle spindle initiates a somatic spinal reflex that causes

1. contraction of the agonist muscle.
2. relaxation of the antagonist muscle.
3. contraction of the antagonist muscle.
4. relaxation of the agonist muscle.
   a) 1 only
   b) 2 only
   c) 3 only
   d) 4 only
   e) 1 and 2

Answer 20

e) 1 and 2

Question 21

In response to a tendon being stretched excessively, a tendon organ initiates a somatic spinal reflex that causes

1. contraction of the agonist muscle.
2. relaxation of the antagonist muscle.
3. contraction of the antagonist muscle.
4. relaxation of the agonist muscle.
   a) 1 only
   b) 2 only
   c) 3 only
   d) 4 only
   e) 3 and 4

Answer 21

e) 3 and 4

Question 22

A somatic spinal reflex that involves one effector muscle being stimulated while the opposing muscle is inhibited is called _____ innervation.

a) reversal
b) relaxed
c) representative
d) reciprocal
e) relegated

Answer 22

d) reciprocal

Question 23

Which of following is NOT a function of the spinal reflexes that use muscle spindles and tendon organs as sensors?

a) Awareness of muscle tension in body
b) Prevention of damage to muscles
c) Protection of spinal nerves
d) Prevention of damage to tendons
e) Maintenance of muscle tone

Answer 23

c) Protection of spinal nerves

Question 24

A typical spinal nerve has how many connections to the spinal cord?

a) 1
b) 2
c) 3
d) 4
e) 5

Answer 24

b) 2

Question 25

Which branch of a spinal nerve serves the deep muscles and skin of the posterior surface of the trunk?

a) Meningeal branch
b) Rami communicantes
c) Brachial plexus
d) Posterior ramus
e) Anterior ramus

Answer 25

d) Posterior ramus

Question 26

The thoracic nerves are also called the

a) brachial nerves.
b) lumbar nerves.
c) sacral nerves.
d) cervical nerves.
e) intercostals nerves.

Answer 26

e) intercostals nerves.

Question 27

Where is the subarachnoid space?

a) E
b) F
c) G
d) H
e) I

Answer 27

a) E

Question 28

Where is the subdural space?

a) E
b) F
c) G
d) H
e) I

Answer 28

b) F

Question 29

Where is the arachnoid mater?

a) E
b) F
c) G
d) H
e) I

Answer 29

d) H

Question 30

Where is the pia mater?

a) E
b) F
c) G
d) H
e) I

Answer 30

c) G

Question 31

Which layer is the dura mater?

a) E
b) F
c) G
d) H
e) I

Answer 31

e) I

Question 32

Which of the labeled structures contains cerebral spinal fluid?

a) A
b) D
c) E
d) F
e) All of these choices

Answer 32

a) A

Question 33

Which of the labeled structures carries exclusively sensory information towards the spinal cord?

a) B
b) C
c) F
d) G
e) H

Answer 33

a) B

Question 34

Which of the labeled structures carries exclusively motor information away from the spinal cord?

a) B
b) C
c) F
d) G
e) H

Answer 34

b) C

Question 35

Where is the pia mater?

a) D
b) E
c) F
d) G
e) H

Answer 35

b) E

Question 36

Where is the posterior ramus?

a) B
b) C
c) G
d) H
e) None of these choices

Answer 36

c) G

Question 37

Where is the epidural space?

a) A
b) D
c) E
d) F
e) G

Answer 37

d) F

Question 38

Where is the anterior (ventral) root of a spinal nerve?

a) A
b) B
c) C
d) G
e) H

Answer 38

c) C

Question 39

Where is the posterior median sulcus?

a) A
b) E
c) F
d) H
e) J

Answer 39

a) A

Question 40

Where is the lateral white column?

a) C
b) D
c) G
d) H
e) I

Answer 40

b) D

Question 41

Where is the anterior gray horn?

a) B
b) C
c) H
d) I
e) None of these choices

Answer 41

c) H

Question 42

Where is the anterior white column?

a) B
b) C
c) H
d) I
e) J

Answer 42

d) I

Question 43

Which portion of the spinal cord contains cell bodies and axons of interneurons as well as incoming axons of sensory neurons?

a) B
b) C
c) D
d) H
e) I

Answer 43

b) C

Question 44

Which portion of the spinal cord contains the cell bodies of somatic motor neurons and motor nuclei?

a) B
b) C
c) D
d) H
e) I

Answer 44

d) H

Question 45

Describe the cross-sectional anatomy of the spinal cord.

Answer 45

The spinal cord is slightly flattened in its anterior-posterior dimension. It has two grooves: anterior median fissure and shallower posterior median sulcus. The central canal contains CSF. The gray commissure surrounds the central canal, and forms the cross bar of the H. It contains the axons that connect the two sides of the gray horns (anterior, posterior, lateral). White matter surrounds the gray and is subdivided into columns (anterior, posterior, lateral). The anterior white commissure is anterior to the gray commissure.

Question 46

Describe the gross external anatomy of the spinal cord.

Answer 46

The spinal cord is roughly cylindrical, but slightly flattened anterior/posterior. It extends from the medulla to the superior border of L2. The length ranges from 42-45 cm and is approximately 2 cm in diameter. There is a cervical enlargement from C4-T1 and a lumbar enlargement from T9-T12. The conus medullaris is the tapered inferior end. The filum terminale is an extension of the pia mater that anchors the cord to the coccyx. The cauda equina is the roots of spinal nerves angling inferiorly in the vertebral canal from the end of the spinal cord. 31 pairs of spinal nerves leave the cord at regular intervals through the intervertebral foramina.

Question 47

Name and describe the locations of the four major plexuses of spinal nerves.

Answer 47

Cervical: alongside C1 through C4; 2. Brachial: inferior and lateral to C4 through T1 and superior to rib, posterior to clavicle; 3. Lumbar: lateral to L1 through L4 passing obliquely

posterior to psoas major and anterior to quadratus lumborum; 4. Sacral: L4-S3; anterior to sacrum.

Question 48

Identify and describe the function of each of the components of a spinal reflex arc.

Answer 48

1. Receptor: responds to specific changes in body conditions by producing graded potential; 2. Sensory neuron: conducts impulse from receptor to integrating center in gray matter of spinal cord; 3. Integrating center: site of synapse between sensory and other neurons; decision-making area in gray matter of spinal cord; 4. Motor neuron: conducts impulse from integrating center to effector; 5. Effector: is the structure that promotes change in body conditions by responding to motor nerve impulse, such as a muscle or a gland.

Question 49

Which of the following structures is labeled B in the diagram?

a) Lumbar enlargement
b) Cervical enlargement
c) Conus medullaris
d) Cauda equina
e) Obturator nerve

Answer 49

b) Cervical enlargement

Question 50

Which of the following structures is labeled D in the diagram?

a) Lumbar enlargement
b) Cervical enlargement
c) Conus medullaris
d) Cauda equina
e) Obturator nerve

Answer 50

a) Lumbar enlargement

Question 51

Which of the following structures is labeled G in the diagram?

a) Lumbar enlargement
b) Cervical enlargement
c) Conus medullaris
d) Cauda equina
e) Obturator nerve

Answer 51

d) Cauda equina

Question 52

The structure labeled A in the diagram belongs to which group of spinal nerves?

a) cervical nerves
b) thoracic nerves
c) lumbar nerves
d) sacral nerves
e) coccygeal nerves

Answer 52

a) cervical nerves

Question 53

The structure labeled F in the diagram belongs to which group of spinal nerves?

a) cervical nerves
b) thoracic nerves
c) lumbar nerves
d) sacral nerves
e) coccygeal nerves

Answer 53

c) lumbar nerves

Question 54

The structure labeled I in the diagram belongs to which group of spinal nerves?

a) cervical nerves
b) thoracic nerves
c) lumbar nerves
d) sacral nerves
e) coccygeal nerves

Answer 54

e) coccygeal nerves

Question 55

Which of the following nerves is labeled A in the diagram?

a) phrenic nerve
b) ulnar nerve
c) intercostal nerve
d) femoral nerve
e) tibial nerve

Answer 55

a) phrenic nerve

Question 56

Which of the following nerves is labeled D in the diagram?

a) phrenic nerve
b) ulnar nerve
c) intercostal nerve
d) femoral nerve
e) tibial nerve

Answer 56

c) intercostal nerve

Question 57

Which of the following nerves is labeled E in the diagram?

a) phrenic nerve
b) ulnar nerve
c) intercostal nerve
d) femoral nerve
e) tibial nerve

Answer 57

d) femoral nerve

Question 58

Which of the following nerves is labeled B in the diagram?

a) phrenic nerve
b) axillary nerve
c) intercostal nerve
d) femoral nerve
e) common fibular nerve

Answer 58

b) axillary nerve

Question 59

The nerve labeled A in the diagram arises from which plexus?

a) cervical plexus
b) brachial plexus
c) lumbar plexus
d) sacral plexus
e) coccygeal plexus

Answer 59

a) cervical plexus

Question 60

The nerve labeled B in the diagram arises from which plexus?

a) cervical plexus
b) brachial plexus
c) lumbar plexus
d) sacral plexus
e) coccygeal plexus

Answer 60

b) brachial plexus

Question 61

Which nerve labeled in the diagram does NOT arise from any plexus?

a) A
b) B
c) D
d) E
e) G

Answer 61

c) D

Question 62

Which nerves labeled in the diagram form the sciatic nerve?

a) B and C
b) A and B
c) F and G
d) E and F
e) D and E

Answer 62

c) F and G

Question 63

Which of the following is a virus infection of the peripheral nervous system caused by herpes zoster, a virus that also causes chickenpox?

a) areflexia
b) shingles
c) poliomyelitis
d) amyotrophic lateral sclerosis
e) menigitis

Answer 63

b) shingles

Question 64

Which of the following is a degenerative disease of the spinal cord?

a) amyotrophic lateral sclerosis
b) shingles
c) poliomyelitis
d) areflexia
e) all of these are degenerative diseases of the spinal cord

Answer 64

a) amyotrophic lateral sclerosis

Question 65

Describe the basic anatomy of a spinal nerve plexus.

Answer 65

Axons from the anterior rami of spinal nerves do not go directly to the body structures they supply. Instead, they form networks called plexuses on both the left and right sides of the

body by joining with various numbers of axons from anterior rami of adjacent spinal nerves. Thus, the nerves that emerge from a plexus and innervate body organs contain nerve fibers from multiple spinal nerves.

Question 66

Which of the following regions of the spinal cord contains a conspicuous enlargement?

a) filum terminale
b) cervical region
c) thoracic region
d) sacral region
e) coccygeal region

Answer 66

b) cervical region

Question 67

The area of the skin that provides sensory input to the CNS via one pair of spinal nerve is called

a) a dermatome.
b) a microtome.
c) perineurium.
d) a fascicle.
e) an epitome.

Answer 67

a) a dermatome.

Question 68

Discuss the clinical significance of dermatomes.

Answer 68

Knowing which spinal cord segments supply each dermatome makes it possible to locate damaged regions of the spinal cord. If the skin in a particular region is stimulated but the sensation is not perceived, the nerves supplying that dermatome are probably damaged.

Question 69

A severed obturator nerve will lead into paralysis of which region of the body?

a) Cervical
b) Thoracic
c) Lumbar
d) Thigh
e) Arms

Answer 69

d) Thigh

Question 70

During childbirth, anesthesia is administered into the epidural space of the spinal column between which of the following vertebrae?

1. L4 and L5
2. T3 and T4
3. S4 and S5
4. C3 and C4
   a) 1 only
   b) 2 only
   c) 3 only
   d) 4 only
   e) Both 1 and 4

Answer 70

a) 1 only

Question 71

Which of the following spinal nerves DOES NOT travel through an intervertebral foramen to reach its destination?

a) cervical spinal nerve 1
b) thoracic spinal nerve 12
c) lumbar spinal nerve 2
d) sacral spinal nerve 1
e) cervical spinal nerve 7

Answer 71

a) cervical spinal nerve 1

Question 72

The cell bodies of the sensory neurons that carry information from the periphery to the spinal cord are located in the

a) anterior white commissure.
b) central canal.
c) lateral gray horn.
d) posterior root ganglion.
e) posterior gray horn.

Answer 72

d) posterior root ganglion.

Question 73

Which of the following lists the connective tissue coverings of the axons, fascicles, and entire nerve in the correct order?

a) endoneurium, perineurium, epineurium
b) endoneurium, epineurium, perineurium
c) perineurium, epineurium, endoneurium
d) epineurium, endoneurium, perineurium

Answer 73

a) endoneurium, perineurium, epineurium

Question 74

Which of the following is NOT a common characteristic of dermatomes?

a) Can be used clinically to determine area of spinal cord damage
b) Each dermatome is only served by a single spinal nerve
c) Complete anesthesia of a single dermatome often requires blocking three adjacent spinal nerves
d) Dermatomes are designated based on the cranial or spinal nerve that serves that area of the skin
e) The dermatome serving the face is supplied by the trigeminal cranial nerve

Answer 74

b) Each dermatome is only served by a single spinal nerve

Question 75

Which of the following is NOT a characteristic of the spinothalamic tract?

a) Begins in the spinal cord
b) Terminates in the thalamus
c) Found in the white matter of the spinal cord
d) Carries motor information down the cord
e) Is composed of multiple axons carrying information in the spinal cord

Answer 75

d) Carries motor information down the cord