(1) in meningitis, on passive flexion of the leg on one side, a similar movement occurs in the opposite leg. SYN: contralateral leg sign, contralateral reflex. (2) in meningitis, involuntary flexion of the knees and hips following flexion of the neck while supine. SYN: neck sign.

Brudzinski sign is a physical examination maneuver that is used to assess the presence of meningitis, a serious inflammation of the membranes that surround the brain and spinal cord. It is named after Dr. Josef Brudzinski, who first described the sign in the late 19th century.

During the exam, the patient lies flat on their back with their neck and legs extended. The healthcare professional then gently flexes the patient's neck towards their chest. If the patient involuntarily flexes their hips and knees in response to this movement, it is considered a positive Brudzinski sign.

The presence of a positive Brudzinski sign is indicative of a severe form of meningitis, as this involuntary response is a reflex action that occurs when the meninges are inflamed and irritated. Other signs and symptoms of meningitis include fever, headache, neck stiffness, sensitivity to light, confusion, and seizures. If meningitis is suspected, immediate medical attention is necessary, as this condition can be life-threatening.

It is important to note that a positive Brudzinski sign is not specific to meningitis and can also be present in other conditions that affect the brain and spinal cord, such as brain tumors, encephalitis, and spinal cord injuries. Additionally, some patients may not exhibit a positive Brudzinski sign even if they have meningitis. Therefore, a complete clinical evaluation and diagnostic tests, such as a lumbar puncture, are required to confirm the presence of meningitis or other conditions.