What is the typical landmark orientation of the lumbar facet joints?

What is the typical landmark orientation of the lumbar facet joints?

• A. The facets are oriented largely sagittally, promoting flexion/extension with limited rotation.
• B. The facets are oriented horizontally, promoting rotation.
• C. The facets are oriented vertically, promoting flexion only.
• D. The facets are oriented obliquely, promoting combined motions.

Answer: (A)

Facet orientation in the lumbar region dictates its main movements. The facets here sit in a sagittal alignment, so the joints primarily guide motion in the forward and backward direction—flexion and extension—while resisting rotation. This sagittal plan provides stability and load-sharing when standing and bending, which is essential for the lower back. Other regions have different facet orientations (more coronal in the thoracic region for rotation, more oblique in the cervical region for a mix of motions), but in the lumbar spine, the sagittal arrangement makes flexion/extension the dominant movement with limited rotational ability.

Facet orientation in the lumbar region dictates its main movements. The facets here sit in a sagittal alignment, so the joints primarily guide motion in the forward and backward direction—flexion and extension—while resisting rotation. This sagittal plan provides stability and load-sharing when standing and bending, which is essential for the lower back. Other regions have different facet orientations (more coronal in the thoracic region for rotation, more oblique in the cervical region for a mix of motions), but in the lumbar spine, the sagittal arrangement makes flexion/extension the dominant movement with limited rotational ability.