Abnormal posturing is different from "bad posture" or "slouching." Instead, it involves holding a body position, or moving one or more parts of the body in a certain way.

Abnormal posturing may be a sign of certain injuries to the brain or spinal cord.

Pathologic posturing; Evaluating a person in a coma

Abnormal posturing that occurs with little stimulation is a sign of serious central nervous system damage. Problems with or damage to the nervous system may appear as posturing when a person does certain tasks, such as walking on the sides of the feet, toes, or heels.

Normally when a muscle contracts, the muscles on the opposite side of the joint offer resistance to the contraction. Abnormal posturing occurs when damage to the central nervous system (brain or spinal cord) reduces or prevents opposition to muscle contraction in certain muscle groups.

See the following types of abnormal postures:

• Decerebrate posture -- the arms and legs are out straight and rigid, the toes point downward, and the head arches backward
• Decorticate posture -- the body is rigid, the arms out straight, the fists are tight, and the legs are straight out
• Opisthotonos -- the back is rigid and arching and the head is thrown backwards

An affected person may alternate between different postures as the condition changes.

Injury or swelling of a part of the brain, spinal cord, or nervous system is the most common cause of abnormal posturing. The type of posturing depends on the type and area of the nervous system involved.

• Cerebral edema
• Head injury
• Increased intracranial pressure due to any cause
• Reye syndrome
• Stroke
• Uncal herniation

People with abnormal posturing almost always have reduced consciousness. Anyone who shows symptoms of abnormal posturing should be examined right away by a health care provider.

In some conditions, such as a coma, these behaviors can continue for a long time.

All abnormal posturing should be treated in a hospital. This kind of movement is most often seen in patients who are in a coma. More subtle posturing that is caused by a doctor at a medical visit may not be as serious.

At the hospital, emergency treatment for abnormal posturing must be started right away. This includes placing a breathing tube and providing breathing assistance. The person will likely be placed in the hospital intensive care unit.

The medical history will be obtained from family members. A physical examination will be performed.

Medical history questions may include:

• When did this behavior start?
• Is there a pattern to the occurrences?
• Is it always the same type of posture?
• What other symptoms came before or occurred during the abnormal posturing?
• Is there any history or injury (such as a known head injury)?

The physical examination will include a complete brain and nervous system evaluation.

Tests may include:

• Cerebral angiography
• EEG
• Head CT scan
• Head MRI scan
• Head x-ray
• ICP monitoring (monitoring of the pressure inside the brain)

Berger JR. Stupor and coma. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Bradley: Neurology in Clinical Practice. 5th ed. Philadelphia, Pa: Butterworth-Heinemann Elsevier; 2008:chap 5.

Bleck T. Levels of consciousness and attention. In: Goetz, CG, ed. Textbook of Clinical Neurology. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 1.