synclitism /sing″klitiz′əm/ [Gk, syn + klinein, to lean] , 1. (in obstetrics) a condition in which the sagittal suture of the fetal head is in line with the transverse diameter of the inlet, equidistant from the maternal symphysis pubis and sacrum. This position is usually found on examination either late in pregnancy or early in labor, as the fetal head descends into the pelvic inlet. As labor progresses, posterior asynclitism develops, and, as the head descends farther, anterior asynclitism is evident because of the shape of the true pelvis below the inlet. 2. (in hematology) the normal condition in which the nucleus and the cytoplasm of the blood cells mature simultaneously and at the same rate.