Week 3 Flashcards
(44 cards)
What is demonstrated radiographically on oblique lumbar spine images?
The pars interarticularis and zygapophyseal joints.
What forms the zygapophyseal joints in the lumbar spine?
The superior and inferior articular processes of adjacent vertebrae.
What oblique angle best visualizes upper lumbar zygapophyseal joints?
50 degrees.
What oblique angle best visualizes lower lumbar zygapophyseal joints?
30 degrees.
What is the average oblique angle used for lumbar zygapophyseal joints?
45 degrees.
What does the ‘Scotty dog’ sign represent on an oblique lumbar x-ray?
A visual representation of lumbar anatomy; parts include the ear (superior articular process), eye (pedicle), nose (transverse process), neck (pars interarticularis), front leg (inferior articular process), body (lamina), and tail (spinous process).
What does a ‘broken neck’ on the Scotty dog indicate?
A pars interarticularis defect or spondylolysis.
What is spondylolisthesis?
Anterior slipping of a vertebra, often from bilateral pars defects.
What is the correct patient positioning for an AP lumbar spine?
Patient supine with knees flexed to reduce lumbar lordosis and bring spine parallel to the IR.
What vertebral level aligns with the iliac crest?
L4-L5.
What vertebral level aligns with the lower costal margin?
L2-L3.
Which projection shows downside zygapophyseal joints in lumbar spine?
Posterior obliques (LPO/RPO).
Which projection shows upside zygapophyseal joints in lumbar spine?
Anterior obliques (LAO/RAO).
What projection best visualizes the pars interarticularis?
Oblique lumbar projection (especially at 45 degrees).
What is the recommended SID for lumbar spine projections?
40 inches.
Why use a sponge or angle for lateral L5-S1 projection?
To make the spine parallel to the IR and open the L5-S1 joint space.
What is the CR angle for AP axial L5-S1 projection in males and females?
30 degrees cephalic for males, 35 degrees cephalic for females.
Why are PA projections sometimes preferred for lumbar spine?
They reduce ovarian and breast dose, and better align disc spaces with the beam.
What is the Ferguson method used for?
To differentiate structural vs. compensatory scoliosis curves.
Why are scoliosis series done PA instead of AP?
To significantly reduce radiation dose to the breast and thyroid.
What is F?
L1-L2 Intervertebral disk space
What is D?
Right Inferior Articular Process of L3
What is the term for the frontal view of a structure?
AP projection
What is A?
Right Transverse process of L5
