Thoracic Spine, Sternum, and Ribs Flashcards Preview

633: Human Imaging II > Thoracic Spine, Sternum, and Ribs > Flashcards

Flashcards in Thoracic Spine, Sternum, and Ribs Deck (84):
1

What are the 2 routine thoracic spine projections?

- AP
- lateral

2

What are the 3 special thoracic spine projections?

- Swimmer’s lateral view of upper thoracic region
- Oblique views
- Thoracolumbar or other coned views

3

Why is the entire rib cage not often radiographed in an evaluation?

Due to the great expanse of bone, multiplanar curves, and superimposition of muscular diaphragm

4

The width between opposing paired pedicles is normally __ mm in the thoracic spine

20 mm

5

What 3 lines should be observed in the lateral thoracic view?

- Line 1: anterior vertebral body line
- Line 2: posterior vertebral body line
- Line 3: spinolaminar line

6

What does the spinolaminar line represent?

The junctions of the laminae at spinous processes

7

The thoracic spine is most commonly injured because of ____ forces

flexion

8

What regions of the thoracic spine that are most common injured and why?

Transitional vertebrae (C/T and T/L regions), because they are junctions between relatively immobile thoracic spine and more flexible cervical/lumbar spines

9

At what segmental level do the majority of thoracic spine injuries occur?

T12 - L1

10

Neurological injury complicates __% to __% of all fractures at the thoracic/lumbar level

15% to 20%

11

What form of imaging is used to assess the thoracic and lumbar spine after blunt trauma?

thorax-abdomen-pelvis (TAP) CT scans

12

What form of imaging is used to assess the degree of neural compromise, cord edema, cord contusion, epidural hematoma, nerve root involvement, or ligamentous disruption associated with thoracic spine trauma?

MRI

13

What type of fractures of the vertebral body are the most common spinal injury detectable on radiographs?

Anterior compression fractures

14

_____ forces account for approximately 90%
of compression fractures. What accounts for the remaining 10%?

Flexion

lateral bending

15

What is a significant factor in vertebral body collapse in older adults?

pre-existing osteoporosis

16

Are anterior compression fractures considered stable or unstable? Explain why...

Stable because only the anterior column is involved

17

Why do anterior compression fractures increase in incidence with age?

There is demineralization of the bone which renders the vertebrae less elastic, more brittle, and more prone to fracture.
Dehydration of the NP also renders the disks less resilient to compression

18

What are the 6 radiographic signs of compression fracture?

- step defect
- wedge deformity
- linear zone of impaction
- displaced endplates
- loss of IVD height
- paraspinal edema

19

What does a step defect look like?

The superior endplate is anteriorly displaced causing a step-off of normally smooth concave anterior margin

20

What does a wedge deformity look like?

Because the anterior vertebral body collapses, the vertebral body appears triangular or trapezoidal in appearance

21

What may a wedge deformity lead to?

increased kyphosis and possibly scoliosis if the wedging is lateral

22

What percentage loss of vertebral body height is required for a wedge deformity to be present on a radiograph?

30%

23

What is the linear zone of impaction?

A linear band of increased density apparent beneath involved endplate in a compression fracture

24

What does the linear zone of impaction represent acutely? What does it represent later on?

Acutely it represents the enmeshed trabeculae of the compression fracture
Later it represents callus formation in a healing fracture

25

In what direction do the endplates displace in a compression fracture?

Anteriorly, due to the anterior shearing of the IVDs

26

What characteristics are present on the radiograph when a compression fracture is less than 2 months old?

It has a step defect, wedge deformity, and the linear zone of impaction

27

What characteristics are present on the radiograph when a compression fracture is older?

It only was a wedge deformity

28

How do vertebral body fractures heal?

by both endosteal and periosteal callus formation

29

How long does vertebral body fracture union take?

3-6 months

30

Does vertebral body height return to normal after healing?

No, the wedge deformity persists after healing

31

Do the IVDs heal completely following compression fracture?

Mildly damaged disks may revascularize and function normally.
However, severely torn disks may calcify and form bony ankylosis at that segment

32

What is the standard treatment for vertebral compression fractures?

Non-operative, typically fitted with thoracolumbar spinal orthosis (TLSO) for 4-6 weeks

33

Typically how long do severe symptoms last in vertebral compression fractures?

10-14 days

34

One in ___ women and one in ____ men will have osteoporosis-related fracture in their remaining lifetimes

two

four

35

What types of fractures are the earliest and most common of all osteoporotic fractures

vertebral compression fractures

36

What are vertebral compression fractures commonly associated with?

chronic back pain, limited spine mobility, and social isolation

37

The existence of one previous vertebral fracture increases risk for subsequent vertebral fractures at multiple levels ___fold and hip fractures ___fold

fivefold

threefold

38

What things are compromised as the spine and thorax lose flexibility?

- ambulation impaired due to pain
- compromised heart and lung volume
- stressful compensatory cervical hyperextension required to bring eyes to horizontal

39

What are the 3 characteristics of osteoporosis of the spine on a plain radiograph?

- Increased radiolucency resulting in an "empty box” appearance of vertebral body
- Cortical thinning
- Trabecular changes

40

Where is increased radiodensity first evident in the spine?

at cancellous vertebral bodies

41

Where is thinning of cortical margins first evident in the spine?

at vertebral body margins, especially at endplates, where the cortical outline is normally relatively thick

42

What do trabecular changes in the spine look like?

distinct vertical striations

43

When do wedge deformities occur in those with osteoporosis?

When the spine is put under flexion or axial compressive forces

44

What are 2 other vertebral body deformities that are evident in osteoporotic spines?

- The vertebral bodies may appear biconcave due to chronic microfractures
- The vertebral bodies may appear flat due to a single traumatic event

45

What are flat-appearing vertebrae referred to as?

vertebra plana

46

What types of endplate deformities are evident in osteoporotic spines?

- There are smooth indentations seen in the region of the NP (central)
- There is also sclerosis along the endplates

47

What are Schmorl’s nodes?

Radiolucent nodes in endplates due to focal intrusion of nuclear material into the vertebral body

48

What does DEXA stand for?

Dual energy x-ray absorptiometry

49

What does DEXA measure?

bone mineral density

50

What are the 3 reasons why DEXA is used over qualitative CT?

- less expensive
- exposes patient to less radiation
- more accurate at measuring subtle changes in bone density

51

Define scoliosis

a lateral deviation of the spine from the mid-sagittal plane combined with rotational deformities of vertebrae and ribs

52

What are the 4 pathological changes that occur on the concave side of a scoliotic curvature

- Narrowed disk spaces
- Wedge-shaped vertebral bodies
- Shorter and thinner pedicles and laminae
- Narrowed IVF and spinal canal spaces

53

What are the 2 pathological changes that occur on the convex side of a scoliotic curvature

- Widened rib spaces
- Posteriorly positioned rib cage

54

Scoliotic curves over 5° appear in approximately _% of population

5%

55

Scoliotic curves over 10° appear in approximately _-_% of population

2-4%

56

Scoliotic curves over 25° appear in _ out of 1,000 individuals

1.5

57

Which gender typically has a large scoliotic curve?

females

58

Approximately __% of structural scoliosis cases are termed idiopathic scoliosis because the etiology remains unknown

80%

59

What are the 3 types of idiopathic scoliosis and when do each develop?

- Infantile idiopathic scoliosis appears before age 3
- Juvenile idiopathic scoliosis appears between the ages of 3-10
- Adolescent idiopathic scoliosis (AIS) appears between age 10 and skeletal maturity

60

Scoliotic curves are named by the side of the con___ and in reference to the patient’s right and left sides

convexity

61

What are the 4 distinct scoliosis patterns?

- Right thoracic curve
- Right thoracolumbar curve
- Left lumbar curve
- Left lumbar, right thoracic curve

62

What is the most commonly seen scoliotic curve?

right convex thoracic curve

63

At what spinal levels does a right convex thoracic curve begin and end at?

Begins: T4–T6
Ends: T11–L1

64

At what spinal levels does a thoracolumbar curve begin and end at?

Begins: T4–T6
Ends: L2–L4

65

In which direction does a thoracolumbar curve occur in?

either side, but right is most common

66

At what spinal levels does a lumbar curve begin and end at?

Begins: T11–T12
Ends: L5

67

In which direction does a lumbar curve occur in?

either side, but left is most common

68

What is the most definitive and diagnostic modality in management of patient with scoliosis?

Radiographs

69

What are the 4 purposes radiographs serve in assessing scoliosis?

- To determine or rule out various etiologies of scoliosis
- To evaluate curvature size, site, and flexibility
- To assess skeletal maturity or bone age
- To monitor curvature progression or regression

70

What are the 4 radiographic series projections to diagnose and evaluate scoliosis?

- Erect AP
- Erect lateral
- Erect AP lateral flexion views of spine
- PA left hand

71

Why is a radiograph of the left hand taken when assessing scoliosis?

to provide accurate assessment of skeletal age

72

What are 2 other indicators of skeletal maturity seen on spine radiographs?

- Fusion of vertebral ring apophyses
- Fusion of iliac crest apophysis to ilium

73

What does Risser's sign refer to?

the amount of calcification of the human pelvis as a measure of maturity

74

Where do apophyses typically dirst appear in the pelvis? Describe their progression...

Apophyses first appear at the ASIS's and progress over a year’s time posteromedially to PSIS's

75

Approximately how long does it take for the pelvis to fuse completely?

2-3 years

76

Describe the progression of ossification according to the Risser's sign scale

- Grade 1 is given when the ilium is calcified at a level of 25%
Grade 2 is given when the ilium is calcified at a level of 50%
- Grade 3 is given when the ilium is calcified at a level of 75%
- Grade 4 is given when the ilium is calcified at a level of 100%
- Grade 5 is given when the ilium is calcified at a level of 100% and the iliac apophysis is fused to iliac crest

77

What is the significance of Risser's sign to scoliosis?

When Risser's sign is 5+ skeletal spinal maturity is complete and the progression of the scoliotic curve is strongly inhibited after this point

78

What is another method of measuring scoliotic curves?

The Cobb Method of Measurement

79

Describe the 3 steps to the Cobb method

1) Identify the uppermost involved vertebra of the curve that tilts significantly toward the concavity and a draw line along its superior endplate
2) Identify the lowermost involved vertebra of curve that tilts significantly toward the concavity and a draw line along its inferior endplate
3) Draw perpendicular lines through lines 1 and 2 and measure the resulting intersecting angle. This is the value of the scoliotic curve

80

What are the 4 factors that determine how scoliosis is treated?

- Patient’s skeletal age
- Curve magnitude
- Curve location
- Potential for curve progression

81

What type of curves are at higher risk for progression?

thoracic more so than thoracolumbar or lumbar curves

82

General treatment guidelines for scoliosis fall into 3 groups, what are these 3 groups?

- For patients with curves of minimal magnitude: No active treatment but close observation for months or years to determine whether curve progressing
- For patients with curves b/w 20°-40°: Spinal bracing combined with exercise for several months or years until skeletal maturity reached
- For patients with curves over 50°: Surgical fixation required

83

What is the primary goal f bracing for scoliosis?

To stop the progression of the curve. However, any correction of the curve considered a bonus

84

In patients who have a curve greater than 50° at skeletal maturity what type of surgery is performed?

posterior spinal fusion with paravertebral rods and bone grafts