Neurology-Online

Numbness in the leg

What is numbness in the leg?

A feeling of numbness describes a reduced feeling of feeling. In clinical terms this phenomenon is called hypesthesia. The normal sensation that occurs when the leg is touched, e.g. occurs when stroking, doesn't feel as strong as before. Some people describe this numbness as if the leg was wrapped in cotton. If this numbness is very pronounced, it may also be that the feeling is no longer there when you touch it.

Numbness in the leg can occur on one or both sides, the whole leg can be affected, or only certain areas of the leg. Some people experience such numbness in the leg from situations where the leg fell asleep.

Also read the article on the topic: Numbness in the foot

causes

Leg numbness usually occurs after damage, irritation or narrowing of a nerve or damage to a nerve pathway that supplies the area of the leg or parts of the leg. Such damage can result from a herniated disc in the lumbar spine or from irritation of the sciatic nerve. In addition, numbness can occur due to narrowing of a certain nerve that runs under the inguinal ligament or as a result of multiple sclerosis. Further causes for a decreased feeling in the leg can also be a polyneuropathy or, if it occurs very suddenly, a stroke can also be responsible. There are many other causes of leg numbness as well.

Lumbar disc herniation as a cause of numbness in the leg

A herniated disc in the lumbar spine is an event that can occur as a result of improper loading in the lumbar spine. Here, the intervertebral disc, which is located between two vertebral bodies, is damaged and material can escape from the interior of the intervertebral disc. This material can leak towards the spinal canal in which the spinal cord runs. This can narrow or damage the spinal cord or a nerve root at this location.

In the lumbar spine (lumbar spine for short), nerves in particular run that supply the legs, but also the bladder and the rectum. Depending on which nerve root the herniated disc affects, different areas in the leg can be affected. The L3 nerve root supplies a sensitive area that runs on the thigh from above / outside to the inner area of the knee. The L4 nerve root sensitively supplies an area that runs from the outer edge of the knee over the front of the shin to approximately the inner malleolus. The outside of the lower leg, pulling diagonally up to the big toe, is sensitively supplied by the L5 nerve root. The area of the nerve root S1 supplies an area that runs on the back of the leg on the outer edge to the sole and outer area of the foot.

But not only numbness can occur with a herniated disc. Depending on the area and severity of a herniated disc in the lumbar spine, symptoms such as paralysis, altered sensation, reduced pain, disturbances in defecating bladder and bowel and failure or reduction of reflexes can occur.

Please also read our topic:

Is numbness an indication of a herniated disc
Symptoms of a herniated disc in the lumbar spine

Sciatica irritation as a cause of numbness in the leg

The sciatica is a large nerve (medical: nervus ischiadicus) that runs in the buttocks and back of the thigh until it divides into other nerves in the knee area (nervus fibularis communis and nervus tibialis). The main symptom of sciatic irritation or entrapment is usually pain in the course of the sciatic nerve and its branches. These run on the back of the thigh, lower leg and foot. However, numbness in the area of the nerve supply area or back pain can also occur. Sciatica irritation can have different causes, e.g. Occur as a result of a herniated disc, after surgery in areas where the nerve runs or after inflammation.

Please also read our topic:

Sciatic nerve pinched - what to do?
Cause of lumbar sciatica

Meralgia paraesthtica as a cause of numbness in the leg

This term refers to the symptoms that result from narrowing of a nerve in the leg. This nerve supplies the outside of the thigh in a sensitive manner and is called in technical terms Lateral femoral cutaneous nerve. The nerve passes through a natural constriction in the body, an area below the inguinal ligament. If the nerve is additionally caused by e.g. Pants that are too tight, overweight or constricted during pregnancy can lead to symptoms such as pain and abnormal sensations, which can also include numbness. The pain is usually relieved by flexing the hip joint.

You can find more information in our topic: Meralgia Paresthetica

MS as a cause of numbness in the leg

MS is short for multiple sclerosis. This is a chronic disease of the nervous system in which the nerve sheaths break down and, in the long term, lead to a loss of function of these nerves. Symptoms can also include numbness in the leg if nerve tracts that supply the leg with sensitivity are affected. However, other symptoms of MS may also occur (such as paralysis or impaired vision). The diagnosis of such a serious illness can only be made by a doctor in the neurology department.

Further information on this topic can be found at: Diagnosing MS

Numbness in the leg after a disc surgery

An operation for a herniated disc is usually only performed if there is a very pronounced herniated disc, e.g. if there are bladder and bowel problems or severe paralysis has occurred. There are always potential complications that can arise during surgery. When you have a herniated disc in the lumbar spine, you operate very close to the spinal canal. Thus, after such an operation (the indication of which is carefully weighed), i.a. irritation of a nerve root also occurs. Such irritation can be accompanied by pain or discomfort such as numbness. In the case of upcoming operations, you will usually be informed in detail about the process and possible complications. If you have any concerns, you can also ask the treating doctors questions at any time.

You might also be interested in this topic: Risks of a disc surgery

Can that also be a thrombosis?

A thrombosis in the leg, medically called deep vein thrombosis, can have very different symptoms or none at all. When symptoms occur, they often manifest themselves as redness, swelling, or overheating and pain in the affected leg. Exactly where on the leg these symptoms appear depends on which section of the leg the thrombosis is located. Numbness in the leg after a thrombosis is rarely described.

Also read our topic: Recognize a thrombosis

diagnosis

In order to diagnose the underlying disease for numbness in the leg, the doctor will first have a detailed discussion with you (anamnesis). You should be able to describe the area, course and accompanying symptoms well and also e.g. Know your previous illnesses and medication you have taken. This is usually followed by a physical exam and possibly a blood sample. If the doctor has any suspicions, further diagnostics will be initiated. This can e.g. be in the form of imaging (such as an MRI of the lumbar spine) or a measurement of the nerve conduction velocity in an electroneurography.

Which doctor treats this?

If you feel numb, your GP will likely refer you to a neurologist. Depending on the cause (e.g. after a herniated disc), an orthopedic surgeon can take over the treatment.

Other accompanying symptoms

Symptoms that are often associated with numbness in the leg are abnormal sensations such as tingling or burning, pain in the leg or back, or paralysis. Other accompanying symptoms can include incontinence of the bladder or intestines, numbness in other areas of the body, visual disturbances or decreased reflexes. The accompanying symptoms always depend on the underlying disease.

Back pain when you feel numb in your leg

Back pain associated with numbness in the leg can occur with a herniated disc in the lumbar spine (lumbar spine) area. Pain in the affected leg can also occur, as well as numbness, abnormal sensations, paralysis or reduced reflexes. A doctor should be consulted urgently in case of bladder and bowel problems.

Treatment vs. therapy

The treatment and therapy of numbness in the leg depends on the underlying cause.

If the cause is a herniated disc in the lumbar spine, it is usually treated without surgery (conservative) if it is mild. This usually means physiotherapy and pain treatment. If the herniated disc is very pronounced, e.g. With a disorder of the bladder and bowel emptying or severe paralysis, surgery can also be considered as a therapy.

In the case of meralgia paresthetica, i.e. the nerve constriction under the inguinal ligament, the cause of the pressure increase in the area of the inguinal ligament should be treated. In the case of trousers or belts that are too tight, it is relatively easy, they should simply be left out. A pregnancy that causes such a pressure increase has a regular end. If overweight is the cause, weight loss should be sought.

If multiple sclerosis is the cause of numbness in the leg, it is important to treat it appropriately. It does this in the form of certain drugs. If MS has relapses, the relapse is usually treated with cortisone in the hospital. Basic therapy is also important, for which a range of medications are available. Together with the attending physician, the best medication for the patient's disease is selected. Sometimes the drug also has to be changed if the desired effect has not occurred.

Other treatment options are available for other causes; the exact treatment will be discussed with you by your doctor depending on the cause.

Read more on the topic:

Treatment of a herniated disc
Therapy for MS

Duration

The duration of a feeling of numbness is difficult to define clearly. Often this depends on the cause of the disease and the treatment.

You might also be interested in this topic: Duration of a herniated disc

forecast

The prognosis, i.e. in this case the regression of the numbness, essentially depends on the underlying cause and the start of treatment. If there are many causes, the prognosis is good. However, if a nerve or nerve tract is permanently damaged, the numbness may also persist.

Further information can be found under our topics: Course of a herniated disc