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Flashcards in Hip Joint Deck (89):
1

What kind of joint is the hip?

Ball and socket synovial type joint

2

What is the hip joint between?

The head of the femur and acetabulum of the pelvis

3

What does the hip joint join?

The lower limb to the pelvic girdle

4

What is the hip joint designed to be?

A stable weight bearing joint

5

What is the result of the hip being a stable weight bearing joint?

A large range of movement is sacrificed for stability

6

What does the hip joint consist of?

An articulation between the head of the femur and the acetabulum of the pelvis

7

What is the acetabulum?

A cup-like depression in the lateral side of the pelvis

8

What shape is the head of the femur?

Hemispherical

9

How does the head of the femur fit into the acetabulum?

Fits completely into the concavity

10

What are the acetabular and head of femur covered in?

Articular cartilage

11

Where is the articular cartilage on the acetabulum and head of femur thicker?

At places of weight bearing

12

What do the ligaments of the hip joint act to do?

Increase stability

13

How can the ligaments of the hip joint be divided?

Into two groups, intracapsular and extracapsular

14

What is the intracapsular ligament?

The ligament of the head of the femur

15

Where does the ligament of the head of the femur run?

From the acetabular fossa to the fovea of the femur

16

What does the ligament of the head of the femur enclose?

A branch of the obturator artery

17

What does the branch of the obturator artery comprise?

A small proportion of the hip joint blood

18

What are the extracapsular ligaments?

Iliofemoral 
Pubofemoral 
Ischiofemoral

19

What are the extracapsular ligaments continuous with?

The outer surface of the hip joint capsule

20

Where is the iliofemoral ligament located?

Anteriorly

21

What does the iliofemoral ligament originate from?

The ilium, immediately inferior to the anterior inferior iliac spine

22

Where does the iliofemoral ligament attach?

To the intertrochanteric line in two places

23

What does the attachment of the iliofemoral ligament give?

The Y shaped appearance of the ligament

24

What does the iliofemoral ligament prevent?

Hyperextension of the hip joint

25

Where is the pubofemoral ligament located?

Anteriorly and inferiorly

26

Where does the pubofemoral ligament attach?

At the pelvis, to the iliopubic eminance and obturator membrane

27

What does the pubofemoral ligament blend with?

The articular capsule

28

What does the pubofemoral ligament do?

Prevents excessive abduction and extension

29

Where is the ischiofemoral ligament located?

Posteriorly

30

Where does the ischiofemoral ligament originate from?

The ischium of the pelvis

31

What does the ischiofemoral ligament attach to?

The greater trochanter of the femur

32

What does the ischiofemoral ligament prevent?

Excessive extension of the femur at the hip joint

33

How is vascular supply to the hip joint achieved?

Via the medial and lateral circumflex femoral arteries, and the artery to the head of the femur

34

What are the circumflex arteries branches of?

The profunda femoris artery

35

Where do the circumflex arteries anastomose?

At the base of the femoral neck

36

What is formed when the circumflex arteries anastomose?

A ring, from which smaller arteries arise to supply the joint itself

37

What is responsible for the majority of the arterial supply to the hip joint?

The medial circumflex femoral artery

38

Why is it the medial, rather than lateral, circumflex femoral artery that provides the majority of the arterial supply to the hip joint?

The lateral circumflex femoral artery has to penetrate through the thick iliofemoral ligament to reach the hip joint

39

What can damage to the medial circumflex artery result in?

Avascular necrosis of the femoral head

40

What is the hip joint innervated by?

The femoral nerve, the obturator nerve, superior gluteal nerve, and the nerve to the quadratus femoris

41

What is the primary function of the hip?

To bear weight

42

What structures increase the stability of the hip joint?

Acetabulum 
Acetabular labrum 
Ligaments 
Muscles

43

How does the acetabulum of the hip increase its stability?

It is deep, encompasses nearly all of the head of the femur, decreasing the probability of the head slipping out of the acetabulum and causing dislocation

44

What is the acetabular labrum?

The fibrocartilaginous collar around the acetabulum

45

What does the acetabular labrum do?

Increases its depth

46

What does the increase in depth produced by the acetabular labrum do?

Provides a large articular surface, thus improving the stability of the joint

47

What ligaments stabilise the hip joint?

Iliofemoral, pubofemoral and ischiofemoral

48

What do the hip ligaments stabilise the joint in conjunction with?

The thickened joint capsule

49

What features of the ligament contribute to their role of strengthening the hip?

Very strong 
Spiral orientation

50

What is the result of the spiral orientation of the ligaments stabilising the hip?

It causes them to become tighter when the joint is extended, which adds stability to the joint and means less energy is needed to maintain a standing position

51

How do muscles and ligaments work at the hip joint?

In a reciprocal fashion

52

How do the muscles and ligaments of the hip joint work anteriorly?

Here the ligaments are strongest, and the medial flexors (located anteriorly) are fewer and weaker

53

How do the muscles and ligaments of the hip joint work posteriorly?

Here the ligaments are weakest, and the medial rotators are greater and stronger- they effectively ‘pull’ the head of the femur into the acetabulum

54

What movements can be carried out at the hip?

Flexion
Extension
Abduction
Adduction 
Medial/lateral rotation

55

What does the degree to which flexion at the hip can occur depend on?

Whether the knee is flexed

56

Why does hip flexion depend on knee flexion?

Because knee flexion releases the hamstrings, and so increases the range of flexion

57

What is extension at the hip joint limited by?

The joint capsule and, in particular, the iliofemoral ligament

58

How do the joint capsule and iliofemoral ligament limit hip extension?

They become taut during extension to limit further movement

59

What produces flexion at the hip?

Iliosoas
Rectus femoris 
Sartorius

60

What produces extension at the hip?

Gluteus maximus 
Semimembranosus 
Semitendinosus 
Biceps femoris

61

What produces abduction at the hip?

Gluteus medius 
Gluteus minimis 
Deep gluteals (piriformis, gemelli etc)

62

What produces adduction at the hip?

Adductors longus, brevis and magnus, pectineus and gracillis

63

What produces lateral rotation at the hip?

Biceps femoris 
Gluteus maximus 
Deep gluteals (piriformis, gemelli etc)

64

What produces medial rotation at the hip?

Gluteus medius and minimus 
Semitendinosus 
Semimembranosus

65

How do fractures to the neck of the femur occur?

In 40 year olds, more likely to occur from balls

66

Who are fractures to the neck of the femur more likely to occur in?

Women

67

Why are fractures to the femoral neck more likely to occur in women?

They generally have more brittle necks from osteoporosis

68

What often happens to the affected limb in a femoral neck fracture?

It is often laterally rotated 
The arteries arising from the medial circumflex artery are usually torn, disrupting the blood supply

69

What can the disruption of the blood supply in femoral neck fractures cause?

Avascular necrosis of the femoral head and neck

70

What happens in a surgical hip replacement?

A plastic socket is cemented to the hip bone to replace the acetabulum, while a stainless steel femoral stem and head replaces the femur

71

When are hip replacements usually performed?

After traumatic injury or in degenerative disease of the joint

72

What are the types of hip dislocation?

Acquired and congenital

73

Who is congenital dislocation of the hip joint more common in?

Girls (8x more likely)

74

How common is congenital dislocation of the hips?

Relatively common

75

What causes congenital dislocation of the hip?

During development, the femoral head is not placed within the acetabulum, resulting in a dislocated joint

76

What are the common symptoms of congenital hip dislocation?

Inability to abduct at the hip joint 
Affected limb is shorter
Positive Trendelenburg sign

77

What does having congenital displacement of the hip predispose to?

Arthritis of the hip later in life

78

How common are acquired dislocations of the hip joint?

Quite uncommon

79

Why are acquired dislocations of the hip joint quite uncommon?

Because of the strength and stability of the joint

80

What are acquired dislocations of the hip usually due to?

Traumatic accidents

81

What are the types of acquired hip dislocation?

Posterior and anterior

82

What is the more common type of acquired hip dislocation?

Posterior

83

What happens in a posterior hip dislocation?

The femoral head is forced posteriorly (backwards), and tears through the inferior and posterior part of the joint capsule, where it is at its weakest

84

What are the signs of a posterior hip dislocation?

The limb becomes shortened and medially rotated

85

What can be damaged in a posterior hip dislocation?

The sciatic nerve

86

Why can the sciatic nerve be damaged in a posterior hip dislocation?

Because it runs posteriorly to the hip joint

87

What would sciatic nerve damage cause?

Paralysis of hamstrings, and muscles distal to the knee

88

What are anterior hip dislocations a consequence of?

Extension, abduction and lateral rotation

89

What is the result of an anterior hip dislocation?

The femoral head ends up anterior and inferior to the acetabulum, and often pulls the acetabular labrum with it