National Board of Chiropractic Examiners (NBCE) Practice Test

Which structure is palpated on the same vertical plane as the PSIS?

1. Sacrum

2. Iliac crest

3. L5 spinous process

4. Pubic symphysis

The correct answer is: L5 spinous process

The L5 spinous process is palpated on the same vertical plane as the posterior superior iliac spine (PSIS). The PSIS is located at the posterior aspect of the iliac crest, and the L5 spinous process is part of the lumbar spine located directly above the sacrum. The alignment of these structures is clinically relevant as the PSIS serves as a landmark for identifying the alignment of vertebrae in the lumbar region. In a typical anatomical position, the PSIS and the spinous process of L5 are aligned vertically, allowing practitioners to assess postural asymmetries or deviations in the lumbar spine. In contrast, the sacrum is located further down at the base of the lumbar spine and is not at the same height as the PSIS, while the iliac crest, although closely related, is located superior to the PSIS. The pubic symphysis is positioned anteriorly, further away from the PSIS, and does not lie in a vertical alignment with it. Understanding these spatial relationships is crucial for effective palpation and assessment in chiropractic practice.