In somatic dysfunction classification of the spine, which biomechanical property governs motion?

In somatic dysfunction classification of the spine, which biomechanical property governs motion?

• A. Facet joint orientation and associated ligamentous constraints.
• B. Intervertebral disc hydration alone.
• C. Spinous process thickness only.
• D. The length of the lamina.

Answer: (A)

Motion in the spine is governed primarily by how the facet joints are oriented and the ligaments that surround them. The facet joints guide the direction and amount of movement between vertebrae, with their capsules and associated ligaments providing passive restraint that limits extremes and stabilizes the segment. While disc height from hydration can influence how much overall movement is possible by changing spacing, it does not set the primary direction or limit of motion the way facet orientation and ligamentous constraints do. Spinous process thickness and lamina length don’t determine the main motion pattern, either. So the facet joint orientation and its ligamentous constraints are the key determinants of spinal motion.

Motion in the spine is governed primarily by how the facet joints are oriented and the ligaments that surround them. The facet joints guide the direction and amount of movement between vertebrae, with their capsules and associated ligaments providing passive restraint that limits extremes and stabilizes the segment. While disc height from hydration can influence how much overall movement is possible by changing spacing, it does not set the primary direction or limit of motion the way facet orientation and ligamentous constraints do. Spinous process thickness and lamina length don’t determine the main motion pattern, either. So the facet joint orientation and its ligamentous constraints are the key determinants of spinal motion.