Describe decerebrate posturing and its clinical significance.

• A. No motor response
• B. Arms flexed and legs extended
• C. Arms and legs extended with wrists pronated; severe brainstem injury and poor prognosis
• D. Localized posturing

Answer: (C)

Decerebrate posturing is an extensor pattern of the limbs, where the arms are straightened and typically pronated, the legs extend, and the body may appear rigid with the head arched. This posture arises from severe brainstem injury, usually involving the upper brainstem (midbrain to upper pons), and it reflects loss of inhibitory control from the cortex with unopposed brainstem-extensor pathways.

Clinically, this is a very serious finding because it indicates a profound brain injury with a poor prognosis. It suggests disruption of the corticospinal and other descending motor tracts and often correlates with coma and potential rapid deterioration. It’s considered more ominous than other postures, such as decorticate rigidity, which indicates different lesion locations and somewhat different prognostic implications.