L4 syndrome

Definition of the L4 syndrome

The spinal cord runs in the spine. From this, nerve tracts emerge on each vertebra in a so-called nerve root. The further nerve tracts then pull into all parts of the body and from there on the same route back to the brain. In this way we can consciously feel the different parts of the body and influence the movement of the muscles. L4 syndrome is an irritation of the nerve root that emerges from the fourth lumbar vertebra. This can lead to disturbances in the affected nerve tract, causing movement problems or unpleasant sensations in the area that is supplied by the nerve tract.

Herniated disc L4 / L5

The intervertebral disc consists of a fibrous disc in which there is a small watery core. It is responsible for dampening the impact of the vertebrae on each other. In the event of incorrect posture or incorrect loading and wear processes, it can happen that part of the intervertebral disc is pushed outwards. One speaks of a protursion. The intervertebral disc can burst open under very high pressure, causing the material to escape. This is called a herniated disc and describes the actual herniated disc. In both cases, the nerve root that emerges at this point can be irritated, depressed and damaged. This then manifests itself in disturbances of movement or sensation in the areas that are supplied by this nerve pathway. In this way, one can deduce the location of the herniated disc based on the symptoms. If L4 and L5 are affected, symptoms particularly arise in the area of ​​the legs.

For more information, we recommend our website to: Herniated disc of L4 / L5

Symptoms of L4 Syndrome

If a herniated disc occurs in the area of ​​the fourth lumbar vertebra, this can be felt, for example, by a weakened extension of the knee. Additionally, bending your hips and pulling your legs together can be difficult. In addition, sensory disturbances or feelings such as pain or a tingling sensation in the area from the lower part of the thigh to the inside of the lower leg can occur. These complaints worsen with a herniated disc under stress. The other causes of L4 syndrome have the same symptoms. Only in the case of a tumor does the pain usually worsen not under stress, but at rest.

In contrast, if there is a herniated disc in the area of ​​the fifth lumbar vertebra, this manifests itself on the one hand in problems when lifting the big toe and foot. On the other hand, the sensory disturbances stretch from the back of the thigh sideways to the front to the back of the foot and the big toe.

Also read: Symptoms of a herniated disc lumbar spine

Symptoms to the right or left

A nerve root emerges from the spinal cord at each vertebra on the left and right, which then runs in a nerve path to all parts of the body. Depending on whether the left or right nerve root is affected, the symptoms appear on the respective side. In most cases, the cause of L4 syndrome is a herniated disc. The intervertebral disc usually only protrudes to one side. However, it can also protrude backwards and thus irritate and depress both nerve roots. This results in movement restrictions and sensory disorders on both sides. If the L4 syndrome is caused by a cyst or tumor, the symptoms are usually limited to only one side. When the spinal canal is narrowed, the left and right sides are often affected.

Causes of L4 Syndrome

In most cases, L4 syndrome is caused by a herniated disc. There are different characteristics. First, part of the intervertebral disc moves outwards and presses on the nerve root. In severe cases, the intervertebral disc can burst and part of it leaks out. Another cause of L4 syndrome can be a narrowing of the spinal canal, in which the spinal cord runs, at the location of the fourth lumbar vertebra. In addition, cysts in this area can irritate or compress the nerve root. In rare cases, benign or malignant tumors that occur at the site can also be a cause of L4 syndrome.

You might also be interested in: Causes of a herniated disc

Appointment with a specialist for a herniated disc?

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Who am I?
My name is dr. Nicolas Gumpert. I am a specialist in orthopedics and the founder of .
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A herniated disc is difficult to treat. On the one hand it is exposed to high mechanical loads, on the other hand it has great mobility.

Therefore, treating a herniated disc requires a lot of experience.
The aim of any treatment is treatment without surgery.

Which therapy achieves the best results in the long term can only be determined after looking at all of the information (Examination, X-ray, ultrasound, MRI, etc.) be assessed.

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Diagnosis of L4 syndrome

To diagnose L4 syndrome, it is important to first talk to the doctor and describe the symptoms precisely. Then some tests, such as the Lasegue test, will be done that indicate irritation to the nerve root. If the L4 syndrome is confirmed, the cause is searched for. Since the most common cause of L4 syndrome is a herniated disc, this is clarified with a magnetic resonance imaging (MRI) examination. Changes in the intervertebral disc and also a protrusion of the intervertebral disc, which the nerve root can press in, become visible. If magnetic resonance tomography cannot be performed, for example because of metallic prostheses in the body, computed tomography is performed.

Further information on this topic can be found at:

  • Diagnosing a herniated disc
  • Bragard test

Positive Lasegue sign in L4 syndrome

The Laseque test is designed to show whether there is irritation of the nerve roots. To perform the test, the patient lies flat on his back. The stretched leg is raised by bending the hip joint. If a stabbing pain occurs in the leg at a flexion angle of 40-60 °, one speaks of a positive Lasegue sign. Based on the exact localization of the pain, one can deduce at what level the nerve root damage is. In L4 syndrome, the pain would be felt on the thigh above the kneecap or on the inside of the lower leg. A positive Lasegue sign can, however, also occur if the nerve root is irritated due to an inflammation of the meninges or if the nerves are irritated at another point in the nerve pathway.

The characteristic muscle of the L4 syndrome

At the spinal cord, nerve tracts emerge in the nerve root and then run to the various muscles of the body. When these nerves are activated, the muscle contracts and thus performs its function. The muscles that receive their nerve tracts from a specific nerve root are called identification muscles. If this is damaged, functional restrictions occur in the corresponding muscles. Therefore, from functional disorders of certain muscles, conclusions can be drawn about damaged nerve roots.The most important characteristic muscle of the L4 syndrome is the quadriceps femoris muscle, which is colloquially known as the quadriceps. It runs from the hip scoop, along the thigh to the knee. If it becomes tense, this leads to a flexion of the hip and an extension of the knee. If there are problems with these movements, this can be an indication of L4 syndrome.

Treatment of L4 Syndrome

Treatment for L4 syndrome depends on the underlying cause. In the case of a herniated disc, there should be good training in incorrect posture and incorrect loading. It has now been proven that immobilization or even bed rest should be avoided, whereas exercise therapy and normal everyday activity should be carried out.

You might also be interested in: Exercises after a herniated disc of the lumbar spine

The pain can be treated with pain medication. The dosage and strength of the medication should only be increased slowly so that there is still room for improvement if the pain worsens. Most people start with drugs such as ibuprofen and diclofenac. There is also the possibility of injecting anesthetic and decongestant medication close to the nerve root under the observation of the CT.

Also read: Therapy of a herniated disc of the lumbar spine

If all of these treatments do not help, an operation will have to be performed in a few cases. The disc material that was pressed out of the disc and is responsible for pressing in the nerve root is removed. Cysts and tumors that may be the cause of L4 syndrome should also be removed by surgery.

For more information, see: Operation of a herniated disc on the lumbar spine

PRT in L4 syndrome

Periradicular therapy is called PRT. This means that treatment is given right around the nerve root. The structures in the back are shown by a CT examination. Then a syringe is brought to the nerve root in a controlled manner. Under CT supervision, it can be ensured that no parts of the spinal cord or the nerves and blood vessels running through it are damaged. After the syringe has been brought in, an anesthetic drug, i.e. a local anesthetic and an anti-inflammatory drug such as cortisone, is injected through the skin. This should lead to the relief of the pain of the L4 syndrome. Cortisone also has a decongestant effect on the irritated area. This reduces the pressure on the nerve root and the cause of the symptoms can be improved, at least for a short time.

For more information, see: Therapy of a herniated disc of the lumbar spine

Duration of a herniated disc

The duration of L4 syndrome depends on the underlying cause. A slight herniated disc, which only leads to swelling and thus to pinching of the nerve root when the affected area is stressed, only causes discomfort for a short time. However, if the herniated disc is very pronounced or if the disc is already so badly damaged that material has leaked out of it, the duration can be significantly longer.

More about this topic can be found: Duration of a herniated disc