According to Fryette's first law, how do the lumbar spine and thoracic spine behave in a neutral position?

Fryette's first law describes the mechanics of spinal motion in a neutral position, indicating that when the spine is in a neutral position (not flexed or extended), side-bending and rotation occur in opposite directions. This principle is particularly relevant for the lumbar and thoracic spine. When side-bending is initiated, the vertebrae will rotate away from the direction of the side-bending. For example, if side-bending occurs to the right, the body will rotate to the left.

This behavior is crucial for understanding the interaction between different movements of the spine, especially when assessing spinal conditions or during manual therapy techniques. Recognizing that side-bending and rotation are coupled in opposite directions under neutral spinal conditions helps clinicians make informed decisions during evaluation and treatment, ensuring appropriate therapeutic interventions.

Other options do not accurately reflect the mechanics described by Fryette's first law, particularly regarding how the spine functions in its neutral state. Understanding this foundational concept supports better clinical reasoning in musculoskeletal evaluations and treatments.