According to Panjabi, which mechanism is not part of the spinal stabilization system?

• A. Motor subsystem
• B. Passive subsystem
• C. Dynamic subsystem
• D. Active muscle stabilization subsystem

Answer: (A)

The spinal stabilization system, as described by Panjabi, includes several components that work together to maintain spinal integrity and function. Among these components, the motor subsystem refers to the neurological control of muscles that stabilize the spine; however, it is not categorized as a mechanistic component of spinal stabilization itself.

The passive subsystem consists of the spinal column's anatomical structures, such as vertebrae, ligaments, and discs, providing mechanical support. The dynamic subsystem involves the active muscle contractions that dynamically stabilize the spine during movement. The active muscle stabilization subsystem encompasses the muscle activity that provides stability through tension and control mechanisms.

Thus, identifying the motor subsystem as not being part of the spinal stabilization system highlights understanding that it is involved in the control and coordination of the other components rather than being a structural or mechanical element itself. This distinction is crucial for a comprehensive understanding of spinal biomechanics and rehabilitation strategies in orthopedic practice.