CAMRT Radiography Practice Exam

In reference to the midsagittal plane, how do the zygapophyseal joints open in lumbar vertebrae?

1. 5-10 degrees anteriorly

2. 90 degrees anteriorly

3. 15-20 degrees anteriorly

4. 30 degrees laterally

The correct answer is: 15-20 degrees anteriorly

The zygapophyseal joints in the lumbar vertebrae open 15-20 degrees anteriorly in relation to the midsagittal plane. This orientation is significant for understanding the anatomy and function of the lumbar spine, particularly during imaging and positioning. The 15-20 degrees anterior opening of the zygapophyseal joints allows for optimal intervertebral mobility and contributes to the stability and flexibility of the lumbar region. This angle enhances the ability to flex and extend while also permitting limited rotational movements. When performing lumbar spine radiographic exams, it's essential to position the patient in such a way that the zygapophyseal joints are visualized clearly, necessitating an understanding of this joint orientation. Other angles of opening, such as 5-10 degrees or 90 degrees anteriorly, do not accurately represent the anatomical characteristics of the lumbar spine, as the angle of the zygapophyseal joints is specifically adapted for the lumbar region's functional requirements. Meanwhile, lateral angles do not apply when discussing the anterior opening in relation to the midsagittal plane, as this term specifically references an orientation that does not include lateral positioning relevant to the zygapophyseal joints.