Neuroanatomy Packet - Section 4 Flashcards

1
Q

How would a descending tract carry information from the brain to influence motor neurons indirectly?

A

Through interneurons

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2
Q

What makes up a mixed spinal nerve?

A
  1. Motor axons that innervate particular skeletal muscles (concerned with movements of the neck, trunk, back or limbs)
  2. Sensory axons that innervate corresponding regions of skin and muscle
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3
Q

Name this structure: a sensory region or skin innervated by an individual nerve root.

A

Dermatome

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4
Q

Name this structure: the muscle fibers that receive their motor innervation from a given spinal nerve.

A

Myotome

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5
Q

What is the clinical term for tingling?

A

Paresthesia

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6
Q

What is the clinical term for total loss of sensation?

A

Anesthesia

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7
Q

Name this structure: A network of the ventral rami of spinal nerves that come together and then redistribute themselves with a different arrangement of peripheral nerves.

A

A somatic nerve plexus

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8
Q

A skeletal muscle generally receives its information from:

A

a single peripheral nerve

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9
Q

Name the four main somatic nerve plexi:

A
  1. Cervical
  2. Brachial
  3. Lumbar
  4. Sacral (lumbosacral)
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10
Q

The cervical plexus consists of what spinal nerves?

A

C1-C4

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11
Q

What does the cervical plexus innervate?

A

Skin and muscles associated with the neck

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12
Q

The brachial plexus consists of what nerves?

A

C5-T1

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13
Q

The brachial plexus innervates what?

A

Skin and muscle acting on the upper limb

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14
Q

The lumbar plexus consists of what nerves?

A

L1-L4

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15
Q

What structures does the lumbar plexus innervate?

A

Skin and muscles of lower abdominal wall in the inguinal region
Anterior and medial compartments of the thigh

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16
Q

The sacral/lumbosacral plexus consists of what nerves?

A

L4 (4th and 5th rami) - S4

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17
Q

Where is the sciatic nerve found?

A

The sacral plexus

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18
Q

What is the largest nerve in the body?

A

The sciatic nerve

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19
Q

What does the sacral plexus innervate?

A

Skin and muscles of the gluteal region, posterior compartment of the thigh and all of the leg and foot

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20
Q

What is a spinal segment?

A

The region of the spinal cord from which a specific spinal nerve projects

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21
Q

How many spinal segments are there?

A

31

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22
Q

What spinal segments lack sensory roots?

A

The first (C1) and the last (S4)

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23
Q

At what vertebral level does the spinal cord end in an adult?

A

1st lumbar vertebra

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24
Q

What is the general function of the radial nerve?

A

Extension of all joints in the arm and hand

25
Q

What is the general function of the median nerve?

A

Thumb side of hand and wrist

26
Q

What is the general function of the ulnar nerve?

A

Finger side of hand and wrist

27
Q

What are the two major branches of the sciatic nerve?

A

Tibial, common fibular

28
Q

What are the most common locations for radiculopathies?

A

C6, C7, L5 and S1 (S1 much, much more common than cervical)

29
Q

Where is the location of a peripheral mononeuropathy?

A

This is an injury to a peripheral nerve arising directly from the plexus. The neuropathy could be complete or incomplete.

30
Q

Give an example of an incomplete lesion involved in a peripheral mononeuropathy. What are the resultant symptoms?

A

Entrapment of a nerve within a muscle
Compression of a nerve within a bony tunnel (carpal tunnel, cubital tunnel syndromes).
Symptoms are: loss of sensation or paresthesia and weakness of those muscles supplied by the particular nerve

31
Q

What is a common cause of a plexopathy?

A

Motorcycle accident (any kind of shearing force trauma)

32
Q

A lesion to a spinal nerve, a dorsal or a ventral root is a:

A

radiculopathy

33
Q

Give an example of a radiculopathy.

A

Herniated intervertebral disc that compresses an individual nerve root

34
Q

What are the symptoms of a radiculopathy?

A

Burning or tingling pain radiating down a limb in the dermatome
Diminished sensation over the dermatome supplied by the affected root
Reduced strength in muscles supplied by that spinal nerve (the myotome of the affected root)

35
Q

Why is a dermatomal pattern of injury not strictly precise?

A

Because adjacent dermatomes overlap

36
Q

In a radiculopathy, can you have complete paralysis of any given muscle or group of muscles?

A

No because some axons innervating the muscle will arise in different (adjacent) nerve roots

37
Q

What is a fancy term for cell bodies of gray matter in the spinal cord?

A

perikarya

38
Q

What can be found in the white matter of the spinal cord?

A

Ascending and descending axons connecting the brain and spinal cord
Propriospinal axons which interconnect different segments of the spinal cord

39
Q

What can be found in the intermediate zone of the gray matter of the spinal cord?

A

Mixture of sensory and motor cell bodies

40
Q

A lesion of the _____ will result in loss of pain-temperature sensation contralaterally, below the level of the lesion.

A

spinothalamic tract

41
Q

The fasciculus gracilis and fasciculus cuneatus are collectively termed the:

A

posterior columns

42
Q

What is stereognosis?

A

The ability to identify objects by touching and handling them with eyes closed.

43
Q

A lesion of the posterior columns results in:

A

Decrease in stereognosis and some proprioception ipsilaterally, below the lesion

44
Q

Why is light touch usually spared in unilateral spinal cord lesions?

A

Because light touch combines the pathways of the posterior columns and the anterolateral system, therefore there is always some input spared.

45
Q

T or F: The spinocerebellar tract runs totally ipsilaterally with no decussation.

A

True. Cerebellar lesions will be ipsilateral always.

46
Q

What is the function of the spinocerebellar tract?

A

Unconscious proprioception

47
Q

The superior cerebellar peduncle connects the cerebellum to the:

A

midbrain

48
Q

The middle cerebellar peduncle connects the cerebellum to the:

A

pons

49
Q

The inferior cerebellar peduncle connects the cerebellum to the:

A

medulla

50
Q

The patient has bilateral paralysis, fasiculations and muscle atrophy at the level C8-T1 along with bilateral pain-temperature loss at the level of T1-T2. What is the pathology?

A

Syringomelia, affects crossing of pain-temp fibers (anterior commissure) and perhaps ventral horns

51
Q

Sensory loss over a given dermatome can result from:

A

Peripheral nerve or its entry point to the spinal cord.

52
Q

What is Brown-Sequard syndrome?

A

Hemisection of the right cervical cord. Loss of pain and temp on the left side of the body below the neck, and paralysis and loss of proprioception-stereognosis below the neck on the right.

53
Q

A patient with a tumor experiences loss of pain-temp in the left lower extremity followed by spastic paralysis on the riht. Where is the tumor?

A

In the R anterolateral aspect of the spinal cord, compressing first the right spinothalamic tract and then enlarging to involve the right corticospinal tract.

54
Q

Name this CN: Chews and feels the front of the head

A

5, trigeminal

55
Q

Name this CN: Moves the face, tastes, salivates, cries

A

7, facial

56
Q

Name this CN: Tastes, salivates, monitors carotid body and sinus.

A

9, glossopharyngeal

57
Q

Name thie CN: Tastes, swallows, lifts palate, talks, communicates with thoraco-abdominal viscera.

A

10, vagus

58
Q

Name this CN: turns head, lifts shoulders.

A

11, accessory

59
Q

Nucleus aMbiguous is Motor, in the Medulla, housing what CN nuclei?

A

9 and 10