Nerves of the Upper Limb Flashcards

1
Q

In basic terms what does the brachial plexus do?

A
  • Nervous Supply to the Upper Limb – Including all but 1 Extrinsic Back Muscle
  • Sensory and Motor
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2
Q

What nerves form the brachial plexus?

A

• Anterior Rami of

– C5-8 and T1

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3
Q

What structural pattern/hierarchy defines the brachial plexus?

A

– Roots-Trunks-Divisions-Cords-Nerves/Branches

  • mnemonic; real teenagers drink cold beer
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4
Q

What game launchers does Fraser Chisholm have on his desktop?

A

Epic, Steam and Origin

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5
Q

Describe dermatomes

A
  • Area of skin innervated by a spinal segment
  • Segmental pattern from embryology
  • Variation and overlap
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6
Q

Where does the nervous supply of the skin come from?

A
  • Named nerves supplying skin
  • Named nerves contain afferent neurones from more than 1 spinal level
  • Don’t confuse with dermatomes
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7
Q

What are myotomes?

A
• A group of muscles
innervated by a single
spinal segment 
    • Usually with a
common action
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8
Q

What spinal segment innervates lateral rotation of the glenohumeral joint?

A

C5

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9
Q

What spinal segment innervates medial rotation of the glenohumeral joint?

A

C6 C7 C8

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10
Q

What spinal segment innervates abduction of the glenohumeral joint?

A

C5

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11
Q

What spinal segment innervates adduction of the glenohumeral joint?

A

C6 C7 C8

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12
Q

What spinal segment innervates flexion of the glenohumeral joint?

A

C5

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13
Q

What spinal segment innervates extension of the glenohumeral joint?

A

C6 C7 C8

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14
Q

What spinal segment innervates flexion of the elbow joint?

A

C5 C6

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15
Q

What spinal segment innervates extension of the elbow joint?

A

C6 C7

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16
Q

What spinal segment innervates flexion of the wrist?

A

(C6) C7

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17
Q

What spinal segment innervates extension of the wrist?

A

C6 (C7)

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18
Q

What spinal segment innervates pronation of the radio-ulnar joints?

A

C7 C8

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19
Q

What spinal segment innervates supination of the radio-ulnar joints?

A

C6

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20
Q

What spinal segment innervates digital flexion of the metcarpo-phalangeal and interphalangeal joints?

A

(C7) C8

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21
Q

What spinal segment innervates digital extension of the metcarpo-phalangeal and interphalangeal joints?

A

C7 (C8)

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22
Q

What spinal segment innervates lateral and medial abduction of the third digit of the metcarpo-phalangeal joints?

A

T1

23
Q

What spinal segment innervates lateral and medial adduction of the third digit of the metcarpo-phalangeal joints?

A

Doesn’t happen, the third digit is the centre line so it cannot move towards itself

24
Q

What spinal segment innervates abduction and adduction of digits 2,4 and 5 of the metcarpo-phalangeal joints?

A

T1

25
Q

What feature of named nerves makes them useful for testing nerve roots?

A

• Named nerves will contain efferent neurones from multiple spinal levels

26
Q

What musculoskeletal nomenclature makes naming nerve supply a bit easier?

A

• Muscles in each compartment have the same (named) nerve supply (usually)

27
Q

What was the mantra of the brachial plexus again?

A

– Roots-Trunks-Divisions -Cords-Nerves/Branches

– Real Teenagers Drink Cold Beer

28
Q

Where do the roots of the brachial plexus travel from to reach the plexus in the axilla?

A

from the neck, under the clavicle where they join up with the axillary artery

29
Q

What are the roots of the brachial plexus? (anterior rami)

A
C5
C6
C7
C8
T1
30
Q

What are the trunks of the brachial plexus and from what roots do they form?

A

Superior - from C5 and C6

Middle - from C7

Inferior - from C8 and T1

31
Q

How does one recognise the terminal nerves?

A

They form an M, the middle of which is the median nerve

32
Q

Where do the roots of the brachial plexus lie?

A

In between the scalenus medius and scalenous anterior muscles in the scalene groove

33
Q

Where does Scalenous anterior lie?

A

between the two subclavian vessels (artery and vein)

34
Q

What does the scalene groove sound like?

A

A lizard croc jazz villain from an 80s Spiderman cartoon

35
Q

Whats the best way to learn the brachial plexus?

A

Draw it out lots

36
Q

By what landmark are divisions of the brachial plexus often found?

A

Under the clavicle

37
Q

Discuss cords of the brachial plexus

A

Lateral Medial and Posterior cords made from divisions of trunk

• Named for relation to Axillary artery

  • Ant div of Upper and Middle Trunk form
    • -> Lateral cord
  • All posterior divisions form
    • -> Posterior cord
  • Ant div of inferior Trunk forms
    • -> Medial cord
38
Q

Why can you not see the posterior cord on many diagrams/prosections?

A

Because it is posterior to the axillary artery

39
Q

What are the terminal branches of the brachial plexus?

A

Musculocutaneous Nerve
Median Nerve
Radial (and Axillary) Nerve
Ulnar Nerve

40
Q

What does the musculocutaneous terminal branch of the brachial plexus supply?

A

Motor
– Arm, Anterior Compartment muscles

Sensory
– Lateral Cutaneous nerve of the forearm

41
Q

What does the median terminal branch of the brachial plexus supply?

A

Motor
– Forearm, Anterior compartment
muscles
– Hand, thenar muscles +

Sensory
– 1⁄2 skin of palm

42
Q

What does the ulnar terminal branch of the brachial plexus supply?

A

Motor
– Forearm, 1 1⁄2 muscles
– Hand, small muscles

Sensory
– 1⁄2 skin of hand

43
Q

What does the radial terminal branch of the brachial plexus supply?

A

Motor
– Arm, Posterior
Compartment muscles

Sensory
– Forearm, posterolateral skin
– Hand, dorsal skin

44
Q

What does the axillary terminal branch of the brachial plexus supply?

A

Motor
– Deltiod and Teres Minor Muscles

Sensory
– Skin of supra-lateral arm

45
Q

On the lateral cord of the brachial plexus, how many minor branches are there?

A

3

46
Q

On the posterior cord of the brachial plexus, how many minor branches are there?

A

3

47
Q

On the medial cord of the brachial plexus, how many minor branches are there?

A

4

check location of this

48
Q

Discuss the minor branches of the brachial plexus

A
• Meet them again regionally
• May also encounter
.   – Intercostal brachial nerve (T2) 
.       • Cutaneous in axilla
• Nerve to subcalvius
.   • Small muscle that anchors and stabilises clavicle
• Suprascapular nerve
.   – Suprascapular foramen
.       • Artery above, nerve below
49
Q

What are the two most common causes of brachial plexus injuries?

A

Obstetric and traumatic

50
Q

Discuss upper brachial plexus injuries

A

(Erb’s palsy)
– Roots C5, 6
– “Waiters Tip” appearance
- as limb will be adducted, internally rotated and pronated

51
Q

Discuss lower brachial plexus injuries

A

(Klumpkey’s palsy)
– Roots C8, T1
– Ulnar Claw
– as there is a weakness in intrinsic hand muscles and so abduction and adduction

52
Q

Other than muscle weakness, what is caused as a result of a brachial plexus injury?

A

Sensory deficits in relevant dermatomes

53
Q

What extrinsic back muscle is not innervated by the brachial plexus

A

The trapezius muscle which receives its supply from the accessory nerve (CN XI)