General information
Meralgia paraesthetica (synonyms: Bernhardt-Roth syndrome or Inguinal tunnel syndrome) belongs to the so-called nerve compression syndromes and is caused by compression of the nervus cutaneus femoris lateralis below the inguinal ligament.
Causes
In principle, anyone can fall ill with Meralgia paraesthetica. There are, however, certain factors that favour its occurrence. These include various causes that lead to high pressure on the inguinal ligament and thus on the lateral cutaneus femoris nerve, including obesity, pregnancy, tight jeans or belts. Existing diabetes mellitus and membership of the male sex (there are approximately three men for every woman affected) also increase the probability of this syndrome.
Origin and symptoms
The cutaneus femoris lateralis nerve is constricted or squeezed in its course, which most frequently occurs at its point of passage under the inguinal ligament, since it makes a kink of about 90° here, in accordance with its natural course. The nerve originates directly from the plexus lumbalis and is purely sensitive, i.e. it does not pull into any muscle, but is exclusively responsible for sensation on the skin on the anterior outer side of the thigh. This also explains the symptoms that affected patients describe: The area of the skin supplied by the nerve causes sensations or pain that are often described as burning or needle-stick-like.
Classically, the complaints are reduced when the hip is bent, as this relieves the nerve, whereas pain tends to increase when the hip is stretched. In the further course of the disease, the skin may become hypersensitive in some cases, so that even wearing clothes causes severe pain, or that the pain and feeling in general is severely restricted at this particular point (this is called hypalgesia or hypaesthesia). About one in ten of those affected have problems on both sides.
The pinching of a skin nerve in the area of the inguinal ligament causes pain in the thigh. Pain caused by pressure on a nerve is usually dull and burning. Some patients describe it as an electrifying feeling.
In case of paraesthesias, the pain occurs on the outside of the thigh. This area is normally sensitively innervated by the nerve. If the nerve is damaged in its course, there is also a numbness or unpleasant tingling sensation. Pain also occurs in the area of the inguinal ligament itself as part of the compression of the sensitive nerve.
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