Biomechanism of childbirth - this is a natural set of rotational and forward movements, which are carried out by the fetus in the process of its movement along the generic canal.
At the end of pregnancy, the fetus is usually set in the longitudinal position. In 95% of cases, there is a head prevalence, and in 3-3.5% a gluteal, the transverse or oblique position of the fetus is rare.
The fetal head is in a state of moderate flexion. its arrow-like structure is located at an equal distance from the lone articulation and the cape (synclette insertion). At the same time, the chin approaches the chest, the arch is arched, the arms are crossed on the chest, the legs are bent at the knees and hips and close to the stomach. At the end of pregnancy, the presenting part is usually as close as possible to the entrance to the small pelvis or somewhat pressed against it.