Thoracic Spine, Sternum, and Ribs Flashcards
What are the 2 routine thoracic spine projections?
- AP
- lateral
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
20 mm
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
flexion
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?
MRI
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%?
Flexion
lateral bending
What is a significant factor in vertebral body collapse in older adults?
pre-existing osteoporosis
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?
30%
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?
3-6 months
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?
10-14 days