Cruralgia or crural neuralgia is pain that follows the course of the crural nerve (now called the femoral nerve).

This nerve arises at the bottom of the spine (or spine) from the meeting of nerve roots emanating from the spinal cord, or spinal cord according to the new nomenclature. This marrow is a cord about 50 cm in length extending the brain and sheltered inside the spine which protects it thanks to the bones of the vertebrae.

In total, 31 pairs of nerves exit to the right and left of the spinal canal: either, from top to bottom, 8 at the neck (cervical roots), 12 from the upper back (thoracic roots), 5 from the lower back ( lumbar roots), 5 at the level of the sacrum and 1 at the level of the coccyx.

The crural nerve is, like all spinal nerves, a nerve that is both sensory and motor: it innervates the front of the thigh and the leg and allows flexion of the thigh on the trunk, extension of the knee as well as the collection of sensitive information from this region (hot, cold, pain, contact, pressure, etc.)