Lumbar Spine Flashcards
Sometimes there appears to be 4 lumbar vertebrae, what is this called?
“sacralization” of L5
Sometimes there appears to be 6 lumbar vertebrae, what is this called?
“lumbarization” of first sacral segment
What are the 5 views of the lumbar spine?
1) Anteroposterior (AP)
2) Left oblique
3) Right oblique
4) Lateral
5) “Coned-down view” of lumbosacral joint
At minimum which views must be taken to perform basic evalution of the lumbar spine?
AP and lateral view
Why does the Coned-down Viewof L5 to S1 subject patients to highest dose of radiation of any standard-plain film view?
The x-rays must penetrate both sides of iliac bones in order to properly view this segment
In an anteroposterior view of the lumbar spine, what do the vertebral bodies represent on the “totem pole”?
Bird’s head
In an anteroposterior view of the lumbar spine, what do the pedicles represent on the “totem pole”?
Bird’s eyes
In an anteroposterior view of the lumbar spine, what do the transverse processes represent on the “totem pole”?
Feathers from bird’s head
What do the lamina and spinous processes form?
The bird’s beak
Which vertebral structure can be assessed to evaluate rotation?
Pedicles
Assessment of alignment in AP view relies upon what bony landmarks?
- The spinous processes should align vertically
- The lateral surfaces of the vertebral bodies should line up vertically
If the spinous processes do not align vertically what is this an indication for?
Rotation at one or more segments
If the lateral surfaces of the vertebral bodies do not align vertically what is this an indication for?
Unilateral compression fracture or osteoporotic collapse of portion of vertebral body
“Double lamina” is a sign of what?
Ssevere spondylolisthesis caused by inferior displacement of L5 on S1 when viewed in AP plane
Why do the laminae in “double lamina” sign appear so close to one another?
Because L5 has slid anteriorly and inferiorly on S1
Oblique views are taken with patient supine and shoulders and lower spine and pelvis rotated ____ side to be imaged
toward
Left oblique with left side rotated
Right oblique with right side rotated
In an oblique view of the lumbar spine, what is represented by the Scottie dog’s eye?
Pedicles
In an oblique view of the lumbar spine, what is represented by the Scottie dog’s ear?
Superior articular facet
In an oblique view of the lumbar spine, what is represented by the Scottie dog’s front leg?
Inferior articular facet
In an oblique view of the lumbar spine, what is represented by the Scottie dog’s tail?
Superior facet on opposite side
In an oblique view of the lumbar spine, what is represented by the Scottie dog’s back leg and back foot?
Spinous process
Inferior articular facet on opposite side
In an oblique view of the lumbar spine, what is represented by the Scottie dog’s muzzle?
Transverse processes
In an oblique view of the lumbar spine, what is represented by the Scottie dog’s neck?
Pars interarticularis
If the Scottie dog appears to be wearing a collar (lucency) what does this indicate?
fracture of pars interarticularis
If there is a fracture of the pars interarticularis what is this diagnostic of?
spondylolysis
At which vertebral level is spondylolysis most common?
L5
How can you tell the difference between spondylolysis and spondylolisthesis?
Spondylolysis is represented by a Scottie dog with a collar
Spondylolisthesis is represented by a decapitated Scottie dog
Spondylolysis vs. spondylolisthesis
Spondylolysis occurs when there is a fracture of the pars portion of the vertebra.
Spondylolisthesis occurs when the vertebra shifts forward due to instability from the pars defect
Spondylolisthesis Grades: Grade 1 = \_\_% displacement Grade 2 = \_\_% displacement Grade 3 = \_\_% displacement Grade 4 > \_\_% displacement
25
50
75
>75
What is retrolisthesis?
Occurs when a superior vertebral body is displaced posteriorly to the vertebrae directly inferior to it
Describe the cone-down view
It is a lateral view of the L5-S1 joint with x-ray energy so high that iliac crests become invisible
Which vertebral bodies are visible in a coned-down view?
Lumbar and sacral bodies
Is the interspace greater between L4- L5 or L5-S1?
L4-L5
What is the Vacuum Phenomenon?
It is an accumulation of gas, principally nitrogen, in crevices within the intervertebral disk or vertebra produced by surrounding soft tissues
In synovial joints the vacuum phenomenon is related to what?
The distraction of articular surfaces
In intervertebral discs the vacuum phenomenon is related to what?
Degenerative processes most of the time.
Rare cases of tumors and infections.
When assessing alignment in the cone-down view what are you looking for?
Making sure that the inferior portion of L5 body is aligned with superior body of S1
Dimensions in superior-inferior and anteroposterior planes should be how large?
approximately equal
Can you assess soft tissue in a cone-down view? Why or why not?
No.
Soft tissue not visible as result of high dosage of radiation, which renders soft tissue invisible
What may the absence of space between two vertebral bodies represent?
- A herniation of the nucleus pulposis
- Failure of embryonic segmentation at one or multiple levels
What are the 3 types of congenital vertebral anomalies?
1) block vertebrae
2) hemivertebrae
3) transitional vertebrae
Describe block vertebrae
are wedge-shaped vertebrae that can cause an angle in the spine (such as kyphosis, scoliosis, and lordosis
Describe hemivertebrae
Occur when adjacent vertebrae fuse through their intervertebral discs due to improper segmentation
Describe transitional vertebrae
Occur when the particular vertebrae take on the characteristics of another. For example the transverse process of the last cervical vertebra may resemble a rib
What is Spondylosis Deformans?
The degeneration of IVDs that is characterized by the formation of bony spurs called Sharpey’s fibers
