Which abnormal posture is described as stiff limbs with bent arms, clenched fists, and straight legs?

• A. Gait
• B. Decorticate posturing
• C. Clonus
• D. FNF test / FTN test

Answer: (B)

Abnormal posturing signals severe disruption of brain control over muscle tone. Decorticate posturing is when the arms are flexed at the elbows with the wrists flexed and fists clenched, held tightly to the body, while the legs are straight. This pattern arises when injury affects areas above the red nucleus in the midbrain, so the cortex can no longer regulate the brainstem, and the brainstem drives flexor posturing of the upper limbs. The description—stiff limbs with bent arms, clenched fists, and straight legs—fits this decorticate pattern.

If the injury were lower in the brainstem (decerebrate posturing), the arms would be extended and the body would appear even more rigid, which is why recognizing the difference matters. The other terms describe different phenomena: gait is how a person walks, clonus is a repetitive, rapid contraction often seen with upper motor neuron irritation, and the remaining terms refer to specific tests rather than posture.