Flashcards in Thoracic Spine, Sternum, and Ribs Deck (84):
What are the 2 routine thoracic spine projections?
What are the 3 special thoracic spine projections?
- Swimmer’s lateral view of upper thoracic region
- Oblique views
- Thoracolumbar or other coned views
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
The width between opposing paired pedicles is normally __ mm in the thoracic spine
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
What does the spinolaminar line represent?
The junctions of the laminae at spinous processes
The thoracic spine is most commonly injured because of ____ forces
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
At what segmental level do the majority of thoracic spine injuries occur?
T12 - L1
Neurological injury complicates __% to __% of all fractures at the thoracic/lumbar level
15% to 20%
What form of imaging is used to assess the thoracic and lumbar spine after blunt trauma?
thorax-abdomen-pelvis (TAP) CT scans
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?
What type of fractures of the vertebral body are the most common spinal injury detectable on radiographs?
Anterior compression fractures
_____ forces account for approximately 90%
of compression fractures. What accounts for the remaining 10%?
What is a significant factor in vertebral body collapse in older adults?
Are anterior compression fractures considered stable or unstable? Explain why...
Stable because only the anterior column is involved
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
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
What does a step defect look like?
The superior endplate is anteriorly displaced causing a step-off of normally smooth concave anterior margin
What does a wedge deformity look like?
Because the anterior vertebral body collapses, the vertebral body appears triangular or trapezoidal in appearance
What may a wedge deformity lead to?
increased kyphosis and possibly scoliosis if the wedging is lateral
What percentage loss of vertebral body height is required for a wedge deformity to be present on a radiograph?
What is the linear zone of impaction?
A linear band of increased density apparent beneath involved endplate in a compression fracture
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
In what direction do the endplates displace in a compression fracture?
Anteriorly, due to the anterior shearing of the IVDs
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
What characteristics are present on the radiograph when a compression fracture is older?
It only was a wedge deformity
How do vertebral body fractures heal?
by both endosteal and periosteal callus formation
How long does vertebral body fracture union take?
Does vertebral body height return to normal after healing?
No, the wedge deformity persists after healing
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
What is the standard treatment for vertebral compression fractures?
Non-operative, typically fitted with thoracolumbar spinal orthosis (TLSO) for 4-6 weeks
Typically how long do severe symptoms last in vertebral compression fractures?
One in ___ women and one in ____ men will have osteoporosis-related fracture in their remaining lifetimes
What types of fractures are the earliest and most common of all osteoporotic fractures
vertebral compression fractures
What are vertebral compression fractures commonly associated with?
chronic back pain, limited spine mobility, and social isolation
The existence of one previous vertebral fracture increases risk for subsequent vertebral fractures at multiple levels ___fold and hip fractures ___fold
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
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
Where is increased radiodensity first evident in the spine?
at cancellous vertebral bodies
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
What do trabecular changes in the spine look like?
distinct vertical striations
When do wedge deformities occur in those with osteoporosis?
When the spine is put under flexion or axial compressive forces
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
What are flat-appearing vertebrae referred to as?
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
What are Schmorl’s nodes?
Radiolucent nodes in endplates due to focal intrusion of nuclear material into the vertebral body
What does DEXA stand for?
Dual energy x-ray absorptiometry
What does DEXA measure?
bone mineral density
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
a lateral deviation of the spine from the mid-sagittal plane combined with rotational deformities of vertebrae and ribs
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
What are the 2 pathological changes that occur on the convex side of a scoliotic curvature
- Widened rib spaces
- Posteriorly positioned rib cage
Scoliotic curves over 5° appear in approximately _% of population
Scoliotic curves over 10° appear in approximately _-_% of population
Scoliotic curves over 25° appear in _ out of 1,000 individuals
Which gender typically has a large scoliotic curve?
Approximately __% of structural scoliosis cases are termed idiopathic scoliosis because the etiology remains unknown
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
Scoliotic curves are named by the side of the con___ and in reference to the patient’s right and left sides
What are the 4 distinct scoliosis patterns?
- Right thoracic curve
- Right thoracolumbar curve
- Left lumbar curve
- Left lumbar, right thoracic curve
What is the most commonly seen scoliotic curve?
right convex thoracic curve
At what spinal levels does a right convex thoracic curve begin and end at?
At what spinal levels does a thoracolumbar curve begin and end at?
In which direction does a thoracolumbar curve occur in?
either side, but right is most common
At what spinal levels does a lumbar curve begin and end at?
In which direction does a lumbar curve occur in?
either side, but left is most common
What is the most deﬁnitive and diagnostic modality in management of patient with scoliosis?
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
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
Why is a radiograph of the left hand taken when assessing scoliosis?
to provide accurate assessment of skeletal age
What are 2 other indicators of skeletal maturity seen on spine radiographs?
- Fusion of vertebral ring apophyses
- Fusion of iliac crest apophysis to ilium
What does Risser's sign refer to?
the amount of calcification of the human pelvis as a measure of maturity
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
Approximately how long does it take for the pelvis to fuse completely?
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
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
What is another method of measuring scoliotic curves?
The Cobb Methodof Measurement
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
What are the 4 factors that determine how scoliosis is treated?
- Patient’s skeletal age
- Curve magnitude
- Curve location
- Potential for curve progression
What type of curves are at higher risk for progression?
thoracic more so than thoracolumbar or lumbar curves
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
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