Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MSK anatomy > The Arm And Brachial Plexus > Flashcards

The Arm And Brachial Plexus Flashcards

1
Q

What is the long bone of the arm

A

Humerus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Proximal parts of the humerus

A

Head
Anatomical neck
Surgical neck
Greater tubercle
Lesser tubercle
Deltoid tuberosity
Radial groove

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Shaft of humerus

A

Expands distally to form bony prominences - medial and lateral epicondyles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Trochlea and capitellum

A

Prominences on the distal humerus which articulate with the trochlear notch of the ulna and the head of the radius at the elbow joint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What prominence of the distal humerus articulates with the trochlear notch of the ulna at the elbow joint

A

Trochlea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What prominence of the distal humerus articulates with the head of the radius at the elbow joint

A

Capitellum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What separates the arm into anterior and posterior compartments

A

Intermuscular septa - which extend from the deep brachial fascia which surrounds the arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How many muscles does the anterior compartment of the arm contain

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

3 muscles in the anterior compartment of the arm

A

Biceps brachii
Brachialis
Coracobrachialis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Role of muscles in the anterior compartment of the arm

A

Flexors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What nerve innervates the 3 muscles in the anterior compartment of the arm

A

Musculocutaneous nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the most superficial muscle in the anterior compartment of the arm

A

Biceps brachii

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do the 2 heads of the biceps brachii attach to

A

The scapula-
Long head = supraglenoid tubercle
Short head = coracoid process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

2 heads of biceps brachii

A

Long and short head

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the long head of the biceps brachii attach to

A

Supraglenoid tubercle of scapula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the short head of the biceps brachii attach to

A

Coracoid process of scapula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Tendon of the long head of the biceps brachii

A

Pierces the capsule of the shoulder joint- helps to stabilise the joint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Common tendon of biceps brachii

A

2 muscle bellies converge to their insertion via a common tendon into the radial tuberosity of the radius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Function of biceps brachii

A

Flexor of elbow and shoulder joint
Supinator of the forearm when the elbow is flexed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Order of muscles from superficial to deep in anterior compartment of the arm

A

Biceps brachii
Brachialis
Coracobrachialis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does the Brachialis attach to

A

Anterior aspect of distal half of shaft of humerus
Crosses the elbow joint to insert upon the ulna tuberosity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Function of Brachialis

A

Flexor of elbow joint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why is the biceps brachii capable of contributing to flexion of the shoulder joint

A

Crosses the shoulder joint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Attachment of the Coracobrachialis

A

Coracoid process of the scapula and medial aspect of middle part of humerus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Function of Coracobrachialis

A

Weak flexor of the shoulder joint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What muscle is located in the posterior compartment of the arm

A

Triceps brachii

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

3 muscle bellies of triceps brachii

A

Converge via a common tendon onto a single insertion point- the olecranonof the ulna

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Olecranon of the ulna

A

Where the common tendon of the triceps brachii inserts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Number of muscle bellies of the triceps brachii

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Number of muscle bellies of the biceps brachii

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

3 muscle bellies of triceps brachii names

A

Long head
Lateral head
Medial hewd

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Origin of long head of triceps brachii

A

Infraglenoid tubercle of scapula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Origin of lateral head of triceps brachii

A

Posterior humerus proximal to radial groove

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Origin of medial head of triceps brachii

A

Posterior humerus distal to radial groove

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Function of triceps brachii

A

Extension of elbow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the most medial part of the triceps

A

Long head

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Function of long head of triceps brachii

A

Contributes to extension of shoulder joint as attaches to scapula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Which nerve innervates the triceps brachii

A

Radial nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Origin of radial nerve

A

Major terminal branch of the brachial plexus
Winds around the posterior aspect of the humerus in the radial groove

40
Q

Which nerve runs in the radial (spiral) groove of the humerus

A

Radial nerve

41
Q

Which spinal nerves form the brachial plexus

A

C5/6/7/8
T1

42
Q

What type of fibres are contained in the brachial plexus

A

Sensory and motor

43
Q

5 segments of the brachial plexus

A

Roots
Trunks
Divisions
Cords
Branches

44
Q

Roots of the brachial plexus

A

5 spinal nerves C5-T1
Found in the neck

45
Q

Trunks of the brachial plexus

A

Found in neck
Superior = C5/C6
Middle = C7
C8/T1 = inferior

46
Q

Divisions of the brachial plexus

A

Each trunk divides into an anterior and posterior division under the clavicle

47
Q

Where do the trunks of the brachial plexus divide

A

Under clavicle

48
Q

Which roots form the superior trunk of the brachial plexus

A

C5/C6

49
Q

Which roots form the middle trunk of the brachial plexus

A

C7

50
Q

Which roots form the inferior trunk of the brachial plexus

A

C8/T1

51
Q

Cords of the brachial plexus

A

Named relative to their position around the second part of the axillary artery- formed from various divisions of the anterior and posterior divisions

52
Q

3 cords of the brachial plexus

A

Lateral cord
Posterior cord
Medial cord

53
Q

What forms the lateral cord of the brachial plexus

A

Anterior divisions of the superior and middle trunk

54
Q

What forms the posterior cord of the brachial plexus

A

Posterior divisions of all the trunks

55
Q

What forms the medial cord of the brachial plexus

A

Anterior division of the inferior trunk

56
Q

Branches of the brachial plexus

A

Located in the axilla
Travel distally to reach the structures that innervate the shoulder, arm, forearm and hand

57
Q

5 branches of the brachial plexus

A

Axillary
Radial
Musculocutaneous
Ulnar
Median

58
Q

What forms the axillary nerve of the brachial plexus

A

Branch from the posterior cord

59
Q

What forms the radial nerve of the brachial plexus

A

Continuation of the posterior cord

60
Q

What forms the Musculocutaneous nerve of the brachial plexus

A

Branch of the lateral nerve

61
Q

What forms the ulnar nerve of the brachial plexus

A

Branch from medial cord

62
Q

What forms the median nerve of the brachial plexus

A

Branches of the lateral and medial cords

63
Q

What does the axillary nerve innervate

A

Deltoid
Teres minor
Small region of skin over the upper lateral arm

64
Q

What is the axillary nerve a branch of

A

Posterior cord

65
Q

Which spinal nerves does the axillary nerve contain fibres from

A

C5/C6

66
Q

Pathway of axillary nerve

A

runs close to the surgical neck of the humerus and is vulnerable to injury in fractures of the surgical neck of the humerus or dislocations of the humeral head.

67
Q

What does the radial nerve innervate

A

Triceps in posterior arm
All muscles in the posterior compartment of the forearm (extensors of the wrist and digits)
Regions of skin over the arm, forearm and hand

68
Q

What does the radial nerve arise from

A

Continuation of posterior cord

69
Q

Which spinal nerves does the radial nerve contain

A

C5-T1

70
Q

When is the axillary nerve vulnerable

A

vulnerable to injury in fractures of the surgical neck of the humerus or dislocations of the humeral head

71
Q

Pathway of the radial nerve

A

runs along the radial (spiral) groove on the posterior surface of the humerus

72
Q

When is the radial nerve vulnerable

A

Mid-shaft fractures of the humerus

73
Q

What does the Musculocutaneous nerve innervate

A

3 muscles in the anterior compartment of the arm: biceps brachii, Brachialis, Coracobrachialis
Region of skin over the lateral forearm

74
Q

What does the Musculocutaneous nerve arise from

A

Lateral cord

75
Q

Which spinal nerves contribute to the Musculocutaneous nerve

A

C5-C7

76
Q

When is the Musculocutaneous nerve vulnerable

A

Rarely injured in isolation

77
Q

What forms the median nerve

A

Contributions of lateral and medial cords

78
Q

What does the median nerve innervate

A

Most of the muscles of the anterior forearm
Small muscles of the thumb
Skin over the lateral aspect of the palm of the hand and over the lateral digits

79
Q

Which spinal nerves contribute to the median nerve

A

C6-T1

80
Q

When is the median nerve vulnerable

A

most vulnerable in the arm as it crosses the anterior aspect of the elbow, in a region called the cubital fossa.

81
Q

What forms the ulnar nerve

A

Continuation of the medial cord

82
Q

Which spinal nerves contribute to the ulnar nerve

A

C8-T1

83
Q

What does the ulnar nerve innervate

A

Most of the small muscles in the hand - vital for fine movement of the digits
Skin over the medial aspect of the hand and medial digits

84
Q

When is the ulnar nerve vulnerable

A

injury behind the medial epicondyle as it lies in a superficial position here (it is easily palpable in this location).

85
Q

Axillary nerve injury

A

Because of its close proximity to the surgical neck of the humerus, the axillary nerve can be injured by fractures in this region (which are common in the elderly) or dislocation of the shoulder joint. The motor fibres of the axillary nerve innervate deltoid and teres minor. Its sensory fibres innervate a patch of skin over the upper lateral arm. Injury to the axillary nerve can therefore result in weakness or paralysis of deltoid – this presents functionally as difficulty abducting the shoulder - and altered sensation or numbness over the upper lateral arm.

86
Q

Radial nerve injury

A

As it travels along the radial groove of the posterior humerus, the radial nerve lies very close to the bone, thus fractures of the humeral shaft can injure the nerve. This can lead to weakness or paralysis of the muscles that are innervated by the radial nerve ‘downstream’ of the point at which the nerve is injured. As most of the radial nerve fibres that supply the triceps have already branched and entered the triceps at the point of the mid-humerus, the triceps itself is not likely to be significantly affected by damage to the radial nerve at this level. However, it will likely affect movements at the wrist because the radial nerve innervates all the muscles of the posterior forearm, which extend the wrist and digits.

87
Q

Ulnar nerve injury

A

The ulnar nerve is vulnerable in the lower arm as it travels behind the medial epicondyle – it is superficial here. Fractures of the medial epicondyle may injure the nerve. Injury to the nerve at this level leads to motor impairments of the hand (as it innervates most of the small muscles of the hand) and causes sensory impairment in the hand (the medial side and the medial 1½ fingers). It is extremely common to knock the elbow in this region - referred to as the ‘funny bone’. A blow to the nerve here causes pain and tingling in the same regions of the hand.

88
Q

Upper brachial plexus injury- Erb’s palsy

A

In this type of injury - which is uncommon - the upper parts of the brachial plexus are affected. It may involve C5 - C6, or C5 - 7. The typical picture is one of paralysis of the lateral rotators of the shoulder and the extensors of the wrist. The affected limb typically appears medially rotated with the wrist flexed.

It is typically caused by trauma – specifically mechanisms that stretch the head away from the shoulder. This may be seen when someone is thrown from a motorbike or a horse. It may also be seen in new-borns if the baby’s shoulder becomes stuck during delivery and its neck is excessively stretched to one side.

89
Q

Lower brachial plexus injury- Klumpke’s palsy

A

This type of injury is also uncommon. The lower parts of the brachial plexus are affected, classically C8 and T1. The typical picture is one of paralysis of the small muscles of the hand. Again, it is most often caused by trauma – specifically mechanisms that forcefully and suddenly pull the arm upwards – this stretches the lower nerves of plexus. It may be sustained in babies during delivery if their arm is forcefully pulled superiorly to aid delivery.

90
Q

Horner’s syndrome

A

Horner’s syndrome is the triad of drooping of the eyelid (ptosis), a constricted pupil (miosis) and lack of sweating (anhidrosis) on one side of the face. It results when the sympathetic nerve supply to the face is interrupted. The T1 spinal nerve carries sympathetic fibres which are destined to supply the face. Therefore, a brachial plexus injury affecting the T1 nerve root may result in Horner’s syndrome as well.

91
Q

Brachial plexus block

A

This is a form of regional anaesthesia and can be used as an alternative to general anaesthesia for surgery on the upper limb. Under ultrasound guidance, local anaesthetic is infiltrated around the nerves of the plexus, which anaesthetises the upper limb.

92
Q
  1. In a patient with a mid-shaft humeral fracture, which movements could you test to try and ascertain whether the radial nerve had been injured?
A

The radial nerve innervates triceps (extends the elbow) and the posterior compartment of the forearm (extends the wrist). Therefore, assessment should involve asking the patient to extend the elbow and then extend the wrist. The patient is asked to do this against gravity and against resistance. In the latter, the examiner applies a little force against the movement the patient is asked to perform – this tests the strength of the movement and again should be compared to the other side.
o Weakness of elbow extension and / or wrist extension would indicate a radial nerve injury. ‘Wrist-drop’ is the term given to the appearance of the wrist and hand when the forearm extensors are weak / paralysed.

93
Q
  1. Describe how the cords of the brachial plexus are situated relative to the second part of the axillary artery.
A

o The lateral cord lies laterally, the medial cord medially and the posterior cord lies posterior to the artery.

94
Q
  1. Which muscle of the upper limb is the most powerful supinator of the forearm? How does the position of the elbow joint affect the action of this muscle?
A

Biceps brachii is the most powerful supinator of the forearm and is much more powerful when the elbow is flexed.

95
Q
  1. Which muscles are innervated by the musculocutaneous nerve? Which area of skin does it carry sensory fibres from?
A

o Biceps brachii, brachialis and coracobrachialis. It supplies sensation to the skin over the lateral forearm. The musculocutaneous nerve becomes the ‘lateral cutaneous nerve of the forearm’ after it has supplied motor fibres to the three muscles above.

96
Q

Which nerve branches form the long thoracic nerve

A

C5/6/7

97
Q

MAMRU

A

Musculocutaneous nerve
Axillary nerve
Median nerve
Radial nerve
Ulnar nerve

MSK anatomy (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions