Innervation
The piriform muscle is nerved by the plexus sacralis. The sacral plexus is a nerve plexus of the sacrum and is formed by the nerves L5 and S1.
Diseases
The great sciatic nerve runs between the piriform muscle and the pelvic bone in the foramen infrapiriforme. In the event of an accident, the piriformis muscle may compress the sciatic nerve, resulting in piriformis syndrome. A rarely known phenomenon is that a herniated disc L5/S1 can lead to a Trendelenburg sign.
In the case of a herniated disc caused by an L5/S1, most physicians directly think of problems in the lower leg, i.e. the foot lifter (tibialis anterior = tibialis anterior muscle, extensor hallucis longus) and the foot descender (gastrocenmius = twin calf muscle). The Trendelenburg sign is caused by paralysis of the piriformis muscle and the resulting inability to stand on one leg because the pelvis can no longer be abducted sufficiently. The consequence of this paralysis is a waddling gait.
Piriformis Syndrome
Muscles must be innervated by nerves, i.e. controlled. In the case of the piriformis muscle, this happens via direct nerves from the sacral plexus. The sacral plexus is a large plexus of nerves located at the sacrum.
The piriformis syndrome describes a constriction of the sciatic nerve, which runs through the foramen infrapiriforme. The ischiadicus originates from the plexus sacralis and supplies the hip, thigh, lower leg and foot muscles. Causes of constriction can be jerky, strong movements of the hip, incorrect posture, injury or even long periods of sitting.
As a result, there is severe pain in the lower back, buttocks and thighs. In some cases it even extends to the groin regions, to the front of the body. Sensitivity disorders such as tingling or numbness are also possible.
The symptoms often occur when the hip is rotated, i.e. when the upper body is turned to the side or in bed. The treatment usually consists of movement therapy, stretching exercises and exercises to build up strength in the muscles of the buttocks and thighs.In addition, massages and, in extreme cases, anti-inflammatory painkillers such as ibuprofen can help. This means that pain can be treated relatively easily, effectively and inexpensively and thus reduced. Nevertheless, the therapy should be taken seriously, otherwise there can be serious consequences such as difficulty walking.