Which statement best describes reflexive SJD?

• A. It is triggered by acute trauma
• B. It causes no muscle guarding
• C. It presents with insidious onset
• D. It involves sustained nociceptive irritation triggering reflexive muscle guarding, and altered mechanics

Answer: (D)

Reflexive SJD arises when ongoing nociceptive input from a cervical spine structure triggers a reflexive muscle guarding response. That guarding is protective but persistent, and it alters how the cervical segments move, leading to changed mechanics of the affected joints. The key is this combination: sustained nociceptive irritation, reflexive muscle guarding, and the resulting altered mechanics. Trauma can be a trigger, but the defining feature is the reflex guarding that changes movement, not just the presence of a trigger or the timing of onset. So the statement that best describes reflexive SJD is the one that specifies sustained nociceptive irritation provoking reflexive guarding with altered mechanics.