Cause: When a muscle is subjected to a load beyond the strength of the muscle (typically sprinting), a rupture occurs. The vast majority of ruptures are partial muscle ruptures. Many of the ruptures at the muscle fastening on the ischiatic bone (tuber ischiadicum) er preceded by lengthy tendinitis (entesopatia tuber ischiadicum) at the same location. In rare cases, the muscle fastening can tear a piece of the ischiatic bone off (especially seen in children as the growth zone on the ischiatic bone (apophysis) increases the risk of tears).
Symptoms: In slight cases a local tenderness is felt after being subjected to load ("sprained muscle", "imminent pulled muscle"). In severe cases sudden shooting pains are felt in the muscle ("partial muscle rupture", "pulled muscle") and in the worst case a sudden snap is felt rendering the muscle unusable ("total muscle rupture"). The following three symptoms are characteristic in connection with muscle injuries: pain upon applying pressure, stretching and activation of the muscle (flexing knee) against resistance. With total ruptures a defect and a swelling (the contracted muscle belly and bleeding) can often be seen and felt in the posterior thigh muscle just below the ischiatic bone and below.
Examination: In very slight cases with only minimal tenderness and no discomfort when walking, medical examination is not necessarily required. The severity of the tenderness is however, not always a measure of the extent of the injury. In cases of more pronounced tenderness or pain, medical examination is required to ensure the diagnosis and treatment. The diagnosis is usually made following normal medical examination, however, if there is any doubt concerning the diagnosis, ultrasound scanning (or MRI scanning) can be performed, as these are the most suitable examinations to ensure the diagnosis (article). The larger the bleeding as assessed by ultrasound scanning, the longer the period needed to heal the injury. Tears on the ischiatic bone will usually be visible on x-rays.
Treatment: Treatment comprises relief and rehabilitation. The aim of the rehabilitation is to strengthen the posterior thigh muscles to enable the muscles to manage the loads which previously caused the rupture. It is only in very rare cases where there is a total rupture at the muscle fastening or tearing of a large piece of bone from the ischiatic bone that surgery is considered (article). Even large ruptures in the thigh muscles will usually be able to be healed and rehabilitated without giving functional disorder (but often cosmetic disfigurement with an irregular thigh muscle).