Chapter 16: Spinal Cord and Spinal Nerves

Question 1

The spinal cord is known as what center due to sensory input and motor output?

Answer 1

Reflex center

Question 2

Label the parts of the spinal cord.

Answer 2

1. T12-L1: Conus medullaris
   - terminal spinal cord at L1
   - stops at age 4
2. Nerve cord: Cauda equina
   - horse tail
3. Coccyx1: Filum teriminale

Question 3

Label the spinal cord meninges.

Answer 3

1. Epidural space (real)
2. Dura mater
3. Subdural space (potential space)
4. Arachnoid mater
5. Subarachnoid space (CSF)
6. Pia mater

Question 4

T/F. On the sectional anatomy of the spinal cord, the posterior refers to the sensory and anterior refers to motor.

Answer 4

True

Question 5

Identify the white matter and gray matter structures.

Answer 5

White matter
1. Posterior funiculus
2. Lateral funiculus
3. White commissure
4. Anterior funiculus
Gray matter
1. Posterior horn
2. Gray commissure
3. Lateral horn
4. Anterior horn

Question 6

The posterior horn contains:

Answer 6

• axons of sensory neurons
• cell bodies of interneurons

Question 7

Describe the 2 sensory receptors of the posterior horn.

Answer 7

1. Somatic sensory receptor: pain, pressure receptors on skin
2. Visceral sensory receptor: stretch in smooth muscle from viscera

Question 8

What is contained in the posterior root ganglion?
A. cell bodies of sensory neurons
B. cerebral spinal fluid
C. cell bodies of motor neurons

Answer 8

A. cell bodies of sensory neurons

Question 9

The anterior horn contains:

Answer 9

• cell bodies of somatic motor neurons that innervate skeletal muscle

Question 10

The lateral horn contains:

Answer 10

• cell bodies of autonomic neurons that innervate smooth muscle, cardiac muscle, and glands

Question 11

Categorize the spinal nerves based on location and include the number.

Answer 11

Cervical part:
C1-C8
Thoracic part:
T1-T12
Lumbar part:
L1-L5
Sacral part:
S1-S5
Coccyx part:
Co1-Co4

Question 12

Distinguish the sensory receptor and the effectors from the image.

Answer 12

Posterior (blue) = sensory
- receptors
Anterior (red) = motor/effector
- muscle

Question 13

Posterior + Anterior roots merge but spinal nerve ….

Answer 13

Splits

Question 14

The cervical plexus innervates the muscles of the:
A. head
B. neck
C. sacrum
D. thoracic cavity

Answer 14

B. neck

Question 15

The brachial plexus supplies:

Answer 15

The upper limbs

Question 16

List the 5 major terminal branches of the brachial plexus that innervates the arm.

Answer 16

1. Axillary nerve
2. Musculocutaneous nerve
3. Radial nerve
4. Median nerve
5. Ulnar nerve

Question 17

Axillary nerve motor innervation and cutaneous innervation is?

Answer 17

Motor: deltoid, teres minor
Cutaneous: superolateral arm

Question 18

Median nerve motor innervation and cutaneous innervation is?

Answer 18

Motor: Anterior forearm muscles, thumb muscles, lateral lumbricals
Cutaneous: dorsal tips

Question 19

Musclulocutaneous nerve motor innervation and cutaneous innervation is?

Answer 19

Motor: Anterior arm muscles
Cutaneous: lateral region of forearm

Question 20

Radial nerve motor innervation and cutaneous innervation is?

Answer 20

Motor: Posterior arm and forearm muscles
Cutaneous: lateral 3 digits, posterior region of arm and forearm

Question 21

Ulnar nerve motor innervation and cutaneous innervation is?

Answer 21

Motor: Anterior forearm muscles, hand muscles
Cutaneous: medial 1 1/2 digits

Question 22

Do the intercostal nerves have a thoracic plexus?

Answer 22

No

Question 23

The lumbar plexus innervates….

Answer 23

• abdomen
• external genitalia
• anterior and medial thigh

Question 24

The sacral plexus innervates….

Answer 24

• pelvis
• posterior thigh
• leg
• foot

Question 25

The main nerve in the sacral plexus is which nerve?

Answer 25

Sciatic nerve (longest in the body)

Question 26

List 5 characteristics of reflexes.

Answer 26

1. stimulus
2. rapid response
3. automatic response
4. involuntary response

Question 27

Describe the 5 steps of the reflex arc in order.

Answer 27

1. Receptor responds
2. Sensory neuron to spinal cord (posterior)
3. Integration (sometimes by interneuron)
4. Motor neuron to effector (anterior)
5. Effector responds (muscle)

Question 28

Classify the following reflex:
Receptor and effector on the same side.

Answer 28

Ispilateral

Question 29

Classify the following reflex:
Sensory from receptor cross over through spinal chord to activate effector on opposite limb

Answer 29

Contralateral

Question 30

Classify the following reflex:
Sensory axons to motor neurons (knee-jerk)

Answer 30

Monosynaptic

Question 31

Classify the following reflex:
Involve interneurons (withdrawl reflex)

Answer 31

Polysynapl

Question 32

Describe what nerve could be damaged due to the following injuries:
- compressed axilla
- neck of humerus broken

Answer 32

Axillary nerve

Question 33

Describe what nerve could be damaged due to the following injuries:
- humeral shaft fracture/elbow
- paralysis of extensor muscles of arm
- anesthesia along posterior arm

Answer 33

Radial nerve

Question 34

Describe what cord could be damaged due to the following injuries:
- improper use of crutches

Answer 34

Posterior cord (axillary and radial nerve)

Question 35

Describe what nerve could be damaged due to the following injuries:
- carpal tunnel syndrome
- paralysis of lateral lumbricals
- anesthesia in part of hand

Answer 35

• Median

Question 36

Describe what nerve could be damaged due to the following injuries:
- fractures/dislocation of elbow
- paralysis of intrinsic hand muscles

Answer 36

Ulnar

Question 37

Describe what trunk could be damaged due to the following injuries:
- excessive separation of neck and shoulder
- any brachial plexus branch

Answer 37

Superior trunk (C5-C6)

Question 38

Describe what nerve could be damaged due to the following injuries:
- arm excessively abducted
- any brachial plexus branch

Answer 38

Inferior trunk (C8-T1)

Question 39

The phrenic nerve innervates ….

Answer 39

The diaphragm