RESUMEN
OBJECTIVE: The aim of the rewiew is to provide complex new informations about anatomy and biomechanics features of the musculus levator ani. Described are risk factors leading to it´s injury and options of imaging the muscle complex (ultrasound, magnetic imaging resonance and 3D modeling). DESIGN: Review. SETTINGS: Departement of Obstetrics and Gynaecology, Hospital in Frýdek-Místek, GONA Co. Ltd , Institute for Mother and Child Prague. RESULTS: Musculus levator ani (MLA) has a complex structure composed mainly of striated muscles. Minority of smooth muscle fibres are also found. Particular parts of the MLA hold together different angles. Inervation is provided through somatic and visceral nerve fibres. During delivery, more there three times stretching of the muscle was observed. Less strenght is needed do the same stretching of the muscle in repeating stress situations. In the MRI studies, two types of injury of the MLA, were found. Predisponed to the injury is medial part of the MLA known as pubovisceral muscle (PVM). PVM has three insertions. The most fragile is it´s medial insertion to the pubic bone described as enthesis. During experimental delivery studies was found, that the pressure in this part of the muscle reach almost 36MPa. CONCLUSION: MLA is a difficult muscle. Because of the ethical reasons we don´t have, and probably never will have informations, how structuraly and elasticaly differs muscle, that was damaged during the delivery, compared to muscle without any damage. Promising are computer delivery simulations. In future, they would give us an answer, how risky is vaginal delivery in concrete expectant mother.