Introduction
A fallen asleep leg is a very common complaint with many possible causes. As a rule, fallen asleep legs occur when nerves are squeezed out by an unfavourable position of the legs. This is particularly common, for example, when sitting for long periods of time when travelling or when using the toilet.
Numbness of the leg, but also tingling in the foot, lower and upper thigh, as well as slight pain are typical symptoms of a leg that has fallen asleep. The symptoms usually disappear after a short period of time, when the cause of the falling asleep leg has been eliminated. If a pinched nerve of this type is ruled out, other, rarer causes which can cause a leg to fall asleep can also be considered. Since the complaints are usually based on an acute compression of the nerve, a therapy apart from the relief of the affected nerve is normally not necessary. If serious diseases are the cause of the leg that has fallen asleep, a therapy should be considered.
Cause
By far the most common cause of a leg falling asleep is the pinching of certain nerves. This pinching can be caused, for example, by sitting for a long time or sitting on awkward seating. If compression of the nerves is ruled out as the cause, a number of other less likely causes can be considered.
Especially if paralysis appears in addition to the symptoms of a fallen asleep leg, a herniated disc should be considered as a cause of the numbness. Back pain occurring at the same time is also a sign that a herniated disc could be the cause of a leg that has fallen asleep. If the nerves leading to the leg are trapped between the spine and the leg by the body’s own structures, complaints of a fallen asleep leg can also occur.
This is for example the case with the so-called piriformis syndrome, where the sciatic nerve is pinched by a muscle and causes the complaints. Rare tumours that press on certain nerves can also cause legs to fall asleep. Circulatory disorders can be the cause of a fallen asleep leg.
In arteriosclerosis, the arteries are calcified and the foot is insufficiently supplied with oxygen. Vascular occlusion by a thrombus can cause symptoms of a fallen asleep leg in addition to the leading symptoms such as severe pain and discoloration of the leg. Systemic diseases such as diabetes mellitus can also lead to numbness in the legs.
If there is a circulatory disturbance in the brain, a number of symptoms can be accompanied by the feeling of a fallen asleep leg. A thrombosis is a blood clot that usually forms in the so-called deep leg veins. Particularly if certain risk factors are present, people are at risk of developing a thrombosis.
These include, in particular, the use of oral contraceptives, as well as prolonged immobility, such as on long journeys or after operations. The symptom of a leg falling asleep is not one of the leading or main symptoms of thrombosis. For example, it is very unlikely to suffer from thrombosis if the symptoms of a leg that has fallen asleep occur alone.
However, especially if other symptoms such as pain, swelling or a dark discolouration of the skin on the leg occur, a thrombosis should be clarified by a doctor. One of the causes of a leg that has fallen asleep is more likely to be a disturbance of the blood circulation in the affected leg. This is usually due to the fact that an artery (feeding vessel) is briefly squeezed, for example by an angled leg in a cross-legged position.
This means that the tissue behind it cannot be supplied with sufficient nutrients and the leg falls asleep. Meralgia is a constriction syndrome of the so-called nervus cutaneus femoris lateralis. This nerve is pinched at the groin, causing burning pain and/or numbness, which can impress like a leg that has fallen asleep.
Normally, the symptoms are improved by a flexion in the hip, as this relieves the nerve. The outer side of the thigh is particularly affected, as the nerve is responsible for supplying this area. A herniated disc in the lumbar spine (lumbar spine) can put pressure on the spinal cord or on nerves that originate there.
Severe nerve damage usually results in shooting pains in the leg. However, if the intervertebral disc only lightly presses on the nerve, the nerve can lose its function very unnoticeably over a longer period of time. Since the nerves are responsible for the feeling in the legs, among other things, a numbness can occur when the nerve is damaged. This feels like a leg that has fallen asleep. – These symptoms in the leg indicate a herniated disc in the lumbar spine
- Slipped disc in the lumbar spine
- Tingling as an indication of a slipped disc
- Deafness as an indication of a slipped disc