Correlation of embryonic movement with palate closure in mice

Previous experiments on palate development led to the hypothesis that neck extension and movements of the lower jaw and tongue are necessary for palate closure. To see if such movements existed at the appropriate developmental stage living embryos were studied at the time of normal palate closure. Spinal cord sections were performed on pregnant mice to permit laparotomy without sedating the embryos, the mice were partially submerged in warm saline, and embryonic movements were observed and photographed. Onset of movement coincided temporally with the onset of palate closure. In addition to movements of limbs and trunk, movements of neck, lower jaw, and tongue were also seen. Activity of embryos could be detected within the intact uterus as well as after removal from the uterus and membranes, and was inhibited by ether. The movements appeared to be spontaneous. These observations are consistent with the hypothesis that the mechanism of palate closure involves muscular movements by the embryo.