What is a neurological symptom Lasegue

The Symptom Lasegue – one of the syndromes of iliac muscle tension, used in neurology to assess the state of the spinal nerves in the pathology of the vertebral column.

A Spastic contraction of the skeletal muscles of the back appear at the infringement of the nerve roots between the vertebrae, or "clips" of muscles. They have value in assessing the prognosis of intervertebral hernias, which can lead to disability.

assessment of the presence of the symptom Lasegue

What is the syndrome of tension

The Symptom Lasegue evaluated by lifting up the feet of the man who lies on his back. The procedure is performed slowly, until the first pain sensation.

Symptom positive if pain arise when the foot is raised to an angle of 30 degrees. Further manipulation will lead to a sharp increase in pain, so much as squeezed nerve, located in the thickness of spazmirovannah iliacus. To bring the patient to such a state is impossible! At the first sign of pain, discontinue the test.

The Specificity of Lasegue – the cessation of pain when bending the knee or hip joint. This symptom appears because the relaxation nerve roots L5 or S1, strangulated paravertebral musculature.

due to the existence of several specific manifestations in assessing the state of spazmirovannah muscles, some doctors distinguished separately Lasegue syndrome which includes following symptoms:

  1. Pain when lifting leg
  2. Cessation of pain when bending the hip and knee joints;
  3. Numbness of the skin of the anterior surface of the thigh when running the test
  4. If the pain appears when the foot is raised more than 70 degrees, it is formed due to compression of the spine, and not the nerve fibers
  5. Radicular pain syndrome is confirmed by lifting the legs to the maximum limit and followed by a rapid flexion of the ankle joint. This should be a spread of pain throughout the leg
  6. When raising a healthy foot while lying on the back must appear painful sensations in the affected limb – cross-symptom Lasegue.

For more qualified assessment of the condition of the spinal nerves was not enough to know what is the Lasegue syndrome tension, because there are additional confirmatory tests: Neri, Wasserman. They help to more accurately confirm the suggestion of a doctor, as there is a subjective assessment of pain by each patient and the individual threshold of nervous sensitivity.

the degree of lifting the legs when the Lasegue syndrome


The Symptom occurs because of stretching of the sciatic nerve or its roots at the slow recovery of the lower extremity. Pain is localized along the course of nerves, as when you run a test occurs to additional irritation.

Anatomically, the spinal roots exit through the intervertebral foramen and continues in the lumbar spine before moving into the nerve fibers for 12 mm. On the basis of these anatomical features may explain the mechanism of action of Lasegue syndrome:

  • In the supine position the sciatic nerve is relaxed;
  • When the lower limb rises to a certain angle with straight knee joint, the nerve is stretched
  • Nerve roots normal pass through the intervertebral foramen. They do not cause pain when a person is in an upright position. Pain on the back of the thigh occur in patients with reduced flexibility – false-positive symptom;
  • If the infringement of the nerve root, or when it is pulled out of the background of intervertebral hernia, any additional tension leads to pain. This situation is observed when raising the limb to an angle of 40 degrees. If the symptoms can be traced at an angle of 60 degrees, must not be reliable because the sciatic nerve may be stretched only up to this value;
  • to Judge positive Lasegue syndrome can be when it occurs in flexion between 10 and 30 degrees.

Special attention deserves the fact that the sciatic nerve is physiologically able to stretch when the load on the nerve roots up to 3 kg. If it is strangulated, or shortened intervertebral hernia, reserve capacity is reduced. In such a situation, any manipulation of the leg leads to destruction of axons (nerve connections) that can form a palsy.

When you run the test should be used with caution. Should stop at the first sign of pain. You cannot perform the manipulation if the patient is under General anesthesia.