Meningeal signs (Kernig, Brudzinski and Lasègue): what they are for

The Kernig, Brudzinski and Lasègue signs are signals that the body gives when certain movements are performed, which allow the detection of meningitis and, therefore, are used by health professionals to help diagnose the disease.

Meningitis is characterized by severe inflammation of the meninges, which are the membranes that cover the brain and spinal cord, and which can be caused by viruses, bacteria, fungi or parasites, leading to symptoms such as intense headache, fever, nausea and stiff neck.

Learn a little more about meningitis in the following video:

How to detect meningeal signs

Meningeal signs must be investigated by a health professional, and performed as follows:

1. Kernig’s sign

With the person lying on their back, the healthcare professional holds the patient’s thigh, flexing it over the hip and then stretching it upwards, while the other remains stretched. Afterwards, do the same with the other leg.

If the movement in which the leg is stretched upwards causes involuntary flexion of the head or the person feels pain or limitations in performing this movement, it could mean that they have meningitis.

2. Sinal de Brudzinski

Also with the person on their back, with their arms and legs stretched out, the healthcare professional should place one hand on the chest and with the other try to bend the person’s head towards the chest.

If, when performing this movement, there is involuntary flexion of the legs and, in some cases, pain, it may mean that the person has meningitis.

3. Lasègue’s sign

With the person lying on their back and their arms and legs stretched out, the healthcare professional flexes the thigh over the pelvis. The sign is positive if the person feels pain in the back of the leg.

These signs are positive for some movements, due to the inflammatory processes that occur during meningitis, causing contraction of the spinal muscles, and are therefore a good tool to help diagnose this disease.

In addition to investigating these signs, the doctor also evaluates other signs and symptoms presented by the person, such as intense headache, neck stiffness, sensitivity to light, fever, nausea and vomiting. Learn about other symptoms that may indicate meningitis.