inclined planes of the pelvis


inclined planes of the pelvis

Anterior and posterior inclined planes of the pelvic cavity, two unequal sections divided by the sciatic spines. In the larger, anterior section, the lateral walls slope toward the symphysis and arch of the pubes; the posterior walls slope in the direction of the sacrum and coccyx. The anterior inclined planes are the declivities over which rotation of the occiput takes place in the mechanism of normal labor. See also: plane