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Flashcards in Humerus Deck (73):
1

What is the humerus?

The bone that forms the upper arm

2

What does the humerus do?

Joints the arm to the shoulder and forearm

3

What does the humerus articulate with?

The proximal region articulates with the scapula and clavicle 
The distal region articulates with the forearm bones (radius and ulna)

4

What is formed when the humerus articulates with the scapula and clavicle?

The shoulder joint

5

What is formed when the humerus articulates with the forearm bones?

Elbow joint

6

What does the humerus act as?

The attachment site for many muscles and ligaments

7

What does the humerus’ role as an attachment site result in?

Various raised roughening on the bony surface

8

What does the proximal region of the humerus articulate with?

The scapula

9

What is formed when the humerus articulates with the scapula?

The glenohumeral (shoulder) joint

10

What are the important anatomical features of the proximal humerus?

The head
Anatomical neck 
Surgical neck 
Greater and lesser tubercles 
Intertubercular sulcus

11

What is a tubercle?

A round nodule

12

What does a tubercle signify?

An attachment site of a muscle or ligament

13

Where does the head of the humerus project?

Medially and superiorly

14

What does the head of the humerus do?

Articulates with the glenoid cavity of the scapula

15

How is the head of the humerus connected to the tubercles?

By the anatomical neck

16

Describe the anatomical neck of the humerus?

Short in width, nondescript

17

Where is the greater tubercle of the humerus located?

Laterally

18

What does the greater tubercle of the humerus have?

An anterior and posterior face

19

What is the function of the greater tubercle?

It serves as attachment sites for three of the rotator cuff muscles

20

What muscles is the greater tubercle the attachment site for?

Supraspinatus 
Infraspinatus 
Teres minor

21

How does the lesser tubercle differ from the greater?

It is much smaller, and more medially located.  It only has an anterior face

22

What is the purpose of the lesser tubercle?

It is the site of attachment for the last rotator cuff muscle- the subscapularis

23

What separates the two tubercles of the humerus?

A deep depression, called the intertubercular sulcus (or groove)

24

What runs through the intertubercular sulcus?

The tendon of the long head of the biceps brachii

25

What are the edges of the intertubercular sulcus known as?

Lips

26

What attaches to the lips of the intertubercular sulcus?

Tendons of the pectoralis major, teres major and latissimus dorsi

27

Where does the surgical neck of the humerus run?

From the tubercles to the shaft of the humerus

28

What is a frequent site of fracture of the proximal part of the humerus?

The surgical neck

29

How does a fracture of the surgical neck of the humerus occur?

By a direct blow to the area, or by falling on an outstretched hand

30

What are the key structures of concern in a surgical neck of the humerus fracture?

Axillary nerve 
Posterior circumflex artery

31

Where does the axillary nerve innervate?

The skin over the lower deltoid (known as the regimental badge area)

32

What will damage to the axillary nerve result in?

Paralysis to the deltoid and teres minor muscles, and so the patient will be unable to abduct their arm 
Sensory innervation to the regimental badge area could be lost

33

What important landmarks does the shaft of the humerus contain?

The deltoid tuberosity 
The radial groove

34

What is the shaft of the humerus the site for?

Attachment for various muscles

35

What is found on the lateral side of the humeral shaft?

The deltoid tuberosity

36

What is the deltoid tuberosity?

A roughened surface where the deltoid muscle attaches

37

What is the radial groove?

A shallow depression

38

Where does the radial groove run?

Diagonally down the surface of the humerus, parallel to the deltoid tuberosity

39

What lies in the radial groove?

The radial nerve and the profunda brachii artery

40

What muscles attach anteriorly to the humerus?

Coracobrachialis
Deltoid 
Brachialis 
Brachioradialis

41

What muscles attach posteriorly to the humerus?

Medial and lateral heads of the triceps

42

What is the problem with a mid shaft fracture of the humerus ?

It could easily damage the radial nerve and profunda brachii artery

43

Why could a mid shaft fracture of the humerus easily damage the radial nerve and profunda brachii artery?

As they are tightly bound in the radial groove

44

What does the radial nerve innervate?

Extensors of the wrist

45

What would be the result of a damaged radial nerve?

The extensors of the wrist would be paralysed, resulting in unopposed flexion of the wrist, known as ‘wrist drop’ 
There is also some sensory loss over the dorsal (posterior) surface of the hand, and proximal ends of the lateral 3 and a half fingers dorsally

46

What does the dorsal region of the humerus articulate with?

The ulna and radius

47

What is formed when the dorsal region of the humerus articulates with the radius and ulna?

The elbow joint

48

What shape does the bone adopt in the dorsal region?

A flattened, almost 2D shape

49

What do the lateral and medial borders of the humerus form?

Medial and lateral supraepicondylar ridges

50

How does the lateral supraepicondylar ridge differ from the medial?

It is more roughened

51

Why is the lateral supraepicondylar ridge more roughened than the medial?

Because it is the site of attachment for many of the extensor muscles in the posterior forearm

52

What is found immediately distal to the supraepicondylar ridges?

The lateral and medial epicondyles

53

What are epicondyles?

Projections of the bone

54

Where can the epicondyles be palpated?

At the elbow- the medial more so because it is much larger

55

Where can the ulnar nerve be palpated?

Along the posterior side of the medial epicondyle

56

Why can the ulnar nerve be palpated at the medial epicondyle?

Because this is where it passes into the forearm

57

What articulates with the ulna?

The trochlea

58

Where is the trochlea located?

Medially

59

Where does the trochlea extend to?

The posterior of the bone

60

What is found lateral to the trochlea?

The capitulum

61

What does the capitulum article with?

The radius

62

What is found along the distal portion of the humerus?

Three depressions, known as the coronoid, radial and olecrannon fossae

63

What do the coronoid, radial and olecrannon fossae accommodate?

The forearm bones during movement at the elbow

64

Where are the common fracture sites of the distal humerus?

Supracondylar fractures 
Medial epicondyle fractures

65

How does a supraepicondylar fracture occur?

By falling on a flexed elbow

66

What kind of fracture is a supraepicondylar?

A transverse fracture, spanning between the two epicondyles

67

What can distal humerus fractures lead to?

Interference to the blood supply of the forearm from the brachial artery 
Damage to the medial, ulnar or radial nerve

68

How can a distal humerus fracture lead to interference of the blood supply from the brachial artery?

Direct damage, or swelling

69

What can interference in forearm blood supply lead to?

Ischaemia, which can cause Volkmann’s ischaemic contracture

70

What is Volkmann’s ischaemic contracture?

Uncontrolled flexion of the hand

71

Why does Volkmann’s ischaemic contracture occur?

Because the flexor muscles become fibrotic and short

72

What could a medial epicondyle fracture damage?

The ulnar nerve

73

What results from damage to the ulnar nerve?

A deformity known as the ulnar claw 
Loss of sensation over the medial 1 and a 1/2 fingers of the hand, on both the dorsal and palmar surfaces