Chapter 12 Workbook Questions

Question 1

Signs and symptoms in a myotomal and dermatomal distribution indicate that the lesion is in what region of the nervous system?

Answer 1

Signs and symptoms in a myotomal and dermatomal distribution indicate that the lesion is in the spinal region.

Question 2

Axons to extrafusal muscle fibers

Name the classification of the listed axons

Answer 2

Aα

Question 3

Axons to intrafusal muscle fibers

Name the classification of the listed axons

Answer 3

Aγ

Question 4

Axons that convey sensory information perceived as pain and temperature

Name the classification of the listed axons

Answer 4

Aδ or C

Question 5

Axons that convey sensory information perceived as touch and pressure

Name the classification of the listed axons

Answer 5

Ia

Question 6

What is the most functionally important branch of the cervical plexus?
A. Branch to the sternocleidomastoid muscle
B. Branch to the biceps brachii
C. Branch to the triceps
D. Phrenic nerve
E. Musculocutaneous nerve

Answer 6

D: The phrenic nerve because it innervates the diaphragm.

Question 7

Which one of the plexes innervates the posterior thigh and most of the leg and foot?
	A. Cervical
	B. Brachial
	C. Lumbar
	D. Sacral
	E. None of the above

Answer 7

D: The sacral plexus innervates the posterior thigh and most of the leg and foot.

Question 8

Miniature endplate potentials are essential for which of the following?
A. Inhibiting the action of lower motor neurons
B. Initiating contraction of muscles
C. Preventing atrophy of muscle fibers
D. A and B
E. All of the above

Answer 8

C: Miniature endplate potentials provide trophic factors to skeletal muscle fibers that are essential to prevent atrophy.

Question 9

Trophic changes after denervation include which of the following?
A. Muscle atrophy
B. Shiny skin
C. Brittleness of fingernails and toenails
D. A and B
E. All of the above

Answer 9

E: Tropic changes after denervation include muscle atrophy, shiny skin, and brittleness of fingernails and toenails

Question 10

Rupture of the ulnar nerve, secondary to the fracture of the humerus

What is this type of lesion classified as?

Answer 10

Traumatic severance

Question 11

Decreased sensation in a stocking/glove distribution

What is this type of lesion classified as?

Answer 11

Polyneuropathy

Question 12

Loss of sensory, autonomic, and motor function of the right musculocutaneous and femoral nerves and the left sciatic nerve

What is this type of lesion classified as?

Answer 12

Multiple mononeuropathy

Question 13

Chronic compression of the median nerve resulting in mild demyelination

What is this type of lesion classified as?

Answer 13

Traumatic myelinopathy

Question 14

Crushing injury of the peroneal nerve

What is this type of lesion classified as?

Answer 14

Traumatic axonopathy

Question 15

List at least three specific factors that may cause polyneuropathy.

Answer 15

Polyneuropathy may be caused by diabetes, nutritional deficiency secondary to alcoholism, autoimmune diseases, prolonged use of therapeutic drugs, or exposure to environmental toxins.

Question 16

What sensory changes commonly occur with diabetic polyneuropathy?

Answer 16

Decreased sensation in a stocking/glove distribution, pain, paresthesia, and dysesthesia commonly occur with diabetic polyneuropathy.

Question 17

What autonomic changes may occur with diabetic polyneuropathy?

Answer 17

Cardiovascular, gastrointestinal, genitourinary, and sweating dysfunctions may occur with diabetic polyneuropathy.

Question 18

How is botulinum toxin therapeutically used?

Answer 18

Botulinum toxin interferes with the release of acetylcholine (Ach) at the neuromuscular junction and is used to weaken overactive muscles in dystonia and spasticity.

Question 19

In a recording from a nerve conduction velocity (NCV) study, decreased amplitude of recorded potentials, combined with slowing of NCV, indicates which of the following?
	A. Myelinopathy
	B. Myopathy
	C. Myasthenia gravis
	D. Upper motor neuron lesion
	E. Axonopathy

Answer 19

E: Axonopathy reduces both the amplitude and velocity of recorded potentials during a nerve conduction velocity study. Traumatic myelinopathy causes decreased velocity but usually not amplitude of recorded potentials. Myopathy only affects muscle and so amplitude of recorded potentials is decreased but velocity of conduction is normal. Myasthenia gravis damages ACh receptors on the muscle membrane, so conduction velocity is normal but recorded amplitude decreases with repeated muscle contractions. Because NCV studies only test peripheral nerves, NCV studies are normal in UMN lesions.

Question 20

If NCV studies show that conduction is slowed at a single site in one nerve, yet the NCV is normal throughout the remainder of the nerve and in other nerves, the disorder is characterized as which of the following?
	A. Traumatic myelinopathy
	B. Axonopathy
	C. Severance injury
	D. Myopathy
	E. Polyneuropathy

Answer 20

A: Traumatic myelinopathy is limited to a single site on a nerve, so nerve conduction proximal and distal to the site of myelinopathy is normal.

Question 21

If the NCV is normal along the length of the peripheral nerve, yet the amplitude of the electromyogram (EMG) potential is decreased, the disorder is:
	A. Myelinopathy
	B. Myopathy
	C. Lower motor neuron lesion
	D. Upper motor neuron lesion
	E. Axonopathy

Answer 21

B: Axonopathy reduces both the amplitude and velocity of recorded potentials during a nerve conduction velocity study. Traumatic myelinopathy causes decreased velocity but usually not amplitude of recorded potentials. Myopathy only affects muscle and so amplitude of recorded potentials is decreased but velocity of conduction is normal. Myasthenia gravis damages ACh receptors on the muscle membrane, so conduction velocity is normal but recorded amplitude decreases with repeated muscle contractions. Because NCV studies only test peripheral nerves, NCV studies are normal in UMN lesions.

Question 22

Myasthenia gravis is an autoimmune disease affecting the:
A. Myelin of peripheral nerves
B. ACh receptors at the neuromuscular junction
C. Release of ACh from the presynaptic terminal
D. Storage of calcium in the sarcoplasmic reticulum
E. Alpha motor neurons in the ventral horn of spinal cord

Answer 22

B: Myasthenia gravis is an autoimmune disease that damages ACh receptors on the muscle membrane.

Question 23

Guillian-Barré syndrome is an autoimmune disease that causes:
	A. Necrosis of the alpha motor neuron
	B. Degeneration of the motor endplate
	C. Spasticity
	D. Peripheral demyelination
	E. Degeneration of the C-fiber axons

Answer 23

D: Guillian-Barré syndrome is an autoimmune disease that causes peripheral demyelination. This polyneuropathy has a rapid onset, with progressive paralysis that may require treatment to prevent respiratory failure. The motor system is usually more affected than the sensory system, but deafferentation pain may be severe.

Question 24

Define Hereditary motor and sensory neuropathy (HMSN; also known as Charcot-Marie-Tooth disease)

Answer 24

Genetic neuropathy that begins with paresis of muscles distal to the knee, with resulting foot drop, a steppage gait, frequently tripping, and muscle atrophy. As the disease slowly progresses, muscle atrophy and paresis affect the hands and the ability to sense heat, cold, and painful stimuli decreases. Neuropathic pain is common.