This is a common clinical condition that presents with pain & hyperaesthesia on antero-lateral aspect of thigh along distribution of lateral cutaneous nerve of thigh. The nagging discomfort over the lateral part of thigh happens because of compression of the lateral cutaneous nerve of thigh. This is a common type of entrapment neuropathy where the nerve is compressed.
The lateral cutaneous nerve of thigh arises from lumbar plexus (L2,3). It comes into the thigh by piercing the inguinal ligament approximately 2 cm medial and 2 cm inferior to the anterior superior iliac spine. It supplies the skin on the antero-lateral side of the thigh as far as the knee and also anterior part of gluteal region.
The nerve may be compressed commonly under the inguinal ligament but also at the level psoas muscle and in the fascia lata. The exact cause of compression is unknown in majority of cases but it may be due to trauma, tumours, surgical injury, retroperitoneal haematoma, aortic aneurysm, prolonged pressure from belts etc.