1. skull: skull structure, ossification degree, etc. The brain structure includes brain, cerebral falx, lateral ventricle, third ventricle, thalamus, cerebellum, vermis of cerebellum, posterior fossa cistern, fourth ventricle, etc. When necessary, the coronal section of the brain is displayed to show the corpus callosum.

2.

Heart: it is required to detect the fetal heart according to the head-side deflection method of four-cavity heart plane sound beam. Determine whether the four-chamber heart is symmetrical, whether the structure of the four-chamber heart is abnormal, whether the cross in the center of the heart exists, and whether the left and right atrioventricular connections are abnormal. Measure the fetal heart rate, and observe whether the fetal heart rate is neat and clear whether there is arrhythmia.

3. Spine: Observe the continuity, curvature and ossification of the spine.