M: The pelvis and hip joint

Question 1

How many bones is the pelvic girdle made up of, what are they?

Answer 1

3

Left and right innominate bones, sacrum

Question 2

How many joints are found in the pelvic girdle?

Answer 2

3: 2 sacroiliac joints and the pubic symphysis joint

Question 3

What is the name of the area where the 3 bones making up the innominate bone fuse?

Answer 3

Acetabulum

Question 4

What part of the pelvic girdle articulates with the head of the femur?

Answer 4

Acetabulum

Question 5

What 3 bones make up the innominate bone?

Answer 5

Ilium, ischium and pubic bones

Develop separately

Question 6

What kind of joint is the hip joint?

Answer 6

Ball and socket synovial joint between the head of the femur and the acetabulum of the innominate bone

Question 7

What 3 things provide stability to the hip joint?

Answer 7

1) Acetabular anatomy
2) Fibrous capsule
3) Ligaments

Question 8

Describe the acetabulum?

Answer 8

Smooth crescent shaped articular surface called the lunate surface, this is deficient inferiorly and is called the acetabular notch, the acetabular notch is bridged by the transverse acetabular ligament

Question 9

What bridges the acetabular notch?

Answer 9

Transverse acetabular ligament

Question 10

What is the acetabular labrum, what is its function?

Answer 10

A rim/lip of cartilage

Deepens the articular surface improving stability

Question 11

Describe the properties of the articular capsule of the hip joint?

Answer 11

Strong and dense but still loose to allow the range of movement of the hip joint

Question 12

What are the attachments of the articular capsule of the hip joint?

Answer 12

Proximal - encircles rim of the acetabulum

Distal - femoral neck - intertrochanteric line and greater trochanter

Question 13

What 3 ligaments surround the hip joint and how do they improve stability?

Answer 13

Iliofemoral, pubofemoral, ischiofemoral
Spiral around the hip joint, taut when the hip is extended, pull the femoral head into the acetabulum, improves stability

Question 14

Where does the iliofemoral ligament lie?

Answer 14

covers the hip joint superiorly and anteriorly, from the anterior inferior iliac spine to the femur

Question 15

What role does the iliofemoral ligament play in improving stability?

Answer 15

Strongest ligament. prevents hyperextension of the hip during standing, ‘screws in’ the femoral head

Question 16

Where does the pubofemoral ligament ligament lie?

Answer 16

Covers the hip joint inferiorly and anteriorly

From the iliopubic eminence to the femur

Question 17

What role does the pubofemoral ligament play in improving stability?

Answer 17

Prevents excessive abduction

Question 18

Where does the ischiofemoral ligament lie?

Answer 18

Covers hip joint posteriorly

Question 19

Which is the weakest of the 3 ligaments surrounding the hip joint?

Answer 19

Ischiofemoral ligament

Question 20

Give 2 possible pelvic ring fractures?

Answer 20

1) Pubic rami fracture
2) Open book pelvic fracture - the 2 pubic bones no longer attached, large gap inbetween, unlikely to be an isolated fracture

Question 21

What is meant by #NOF?

Answer 21

Fractured neck of femur (‘hip fracture’)

Question 22

What is particularly worrying about fractures to the pelvic ring?

Answer 22

The pelvis can hold lots of blood - cant see this internal bleeding

Question 23

What are the 3 possible hip dislocations?

Answer 23

1) Posterior dislocation
2) Anterior dislocation
3) Medial dislocation/acetabular fracture

Question 24

How does the limb appear in a posterior dislocation of the hip?

Answer 24

Shortened and internally rotated

Question 25

Posterior dislocation occurs from impact when the lower limb is in what position?

Answer 25

Flexed, internally rotated, adducted

Question 26

What are the possible associated problems in a posterior dislocation of the hip?

Answer 26

Damage to the sciatic nerve | May be associated with acetabular fracture

Question 27

Anterior dislocation tends occur when?

Answer 27

When force is applied during extreme abduction with external rotation of the hip, the femoral head is levered out anteriorly

Question 28

How does the limb appear in an anterior dislocation?

Answer 28

Externally rotated, abducted and flexed

Question 29

How may dislocations of the hip affect the blood supply and what are the possible consequences?

Answer 29

Blood vessels may be torn or stretched Some branches may remain kinked or compressed until the hip is reduced, lack of blood supply leads to avascular necrosis of femoral head

Question 30

What is developmental displacement of the hip?

Answer 30

Congenital abnormality, of varying severity. Can have slight subluxation (femur not in contact with all of acetabulum), low dislocation (femoral head only just not in contact with acetabulum) or high dislocation (femoral head completely above acetabulum)

Question 31

How is developmental displacement of the hip treated?

Answer 31

Child is placed in a cast which holds the lower limb abducted which levers the femoral head back into position in the acetabulum

Question 32

Why should children be examined for abnormalities of the hips?

Answer 32

In order to develop correctly both the acetabulum and the femoral head need to articulate with each other, if not caught early and corrected then the children are likely to have problems walking in the future