Decerebrate rigidity

Abnormal posturing
Classification and external resources
ICD-10	R29.3
ICD-9-CM	781.92
MedlinePlus	003189 003299, 003300
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Abnormal posturing is an involuntary flexion or extension of the arms and legs, indicating severe brain injury. It occurs when one set of muscles becomes incapacitated while the opposing set is not, and an external stimulus such as pain causes the working set of muscles to contract. The posturing may also occur without a stimulus. Since posturing is an important indicator of the amount of damage that has occurred to the brain, it is used by medical professionals to measure the severity of a coma with the Glasgow Coma Scale (for adults) and the Pediatric Glasgow Coma Scale (for infants).

The presence of abnormal posturing indicates a severe medical emergency requiring immediate medical attention. Decerebrate and decorticate posturing are strongly associated with poor outcome in a variety of conditions. For example, near-drowning victims that display decerebrate or decorticate posturing have worse outcomes than those that do not. Changes in the condition of the patient may cause him or her to alternate between different types of posturing.

Posturing can be caused by conditions that lead to large increases in intracranial pressure. Such conditions include traumatic brain injury, stroke, intracranial hemorrhage, brain tumors, and encephalopathy. Posturing due to stroke usually only occurs on one side of the body and may also be referred to as spastic hemiplegia. Diseases such as malaria are also known to cause the brain to swell and cause this posturing effect.

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