Structural Analysis Flashcards
7 cards from real CBP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Structural Analysis flashcards as text
What is the approximate ideal L1-L5 absolute rotation angle in the Harrison lumbar model?
Answer: -40 degrees
The Harrison ideal lumbar model has an L1-L5 ARA of about -40 degrees.
Which geometric shape best describes the Harrison ideal lumbar lordosis?
Answer: A portion of an ellipse
Harrison modeled the lumbar lordosis as an elliptical curve, with more lordosis in the lower segments.
Pelvic incidence equals which combination of sagittal pelvic parameters?
Answer: Pelvic tilt plus sacral slope
Pelvic incidence is a fixed morphologic angle equal to pelvic tilt plus sacral slope.
On a lateral lumbar radiograph, the sacral base angle is measured between the S1 superior endplate and which reference?
Answer: A true horizontal line
The sacral base (Ferguson) angle is the angle of the S1 endplate relative to horizontal.
In the lumbar spine, lateral bending is normally coupled with which motion?
Answer: Axial rotation
Lumbar lateral flexion is coupled with axial rotation of the vertebrae.
Which sagittal finding on a lateral lumbar film best indicates loss of normal lordosis?
Answer: An L1-L5 ARA of -15 degrees
An ARA far below the -40 degree ideal indicates hypolordosis.
In CBP posture analysis, a forward shift of the thoracic cage relative to the pelvis is described as:
Answer: +Tz translation of the thoracic cage
Forward thoracic cage displacement is translation along the z-axis, or +Tz.