The most accurate method of diagnosis is prenatal screening through real-time fetal images. However, since maternal body habitus leads to diagnostic difficulties using this method, MRI and sonography are the most commonly used technique since there is no exposure to ionizing radiation. At the beginning of the second trimester, the central nervous system (CNS) and anatomic structures of the fetus can be clearly visualized and the characteristic malformations of<unk> , such as a shortened trunk, marked lordosis in the cervicothoracic vertebrae, absence or partial absence of the occipital squama, abnormal fusion of vertebrae, closed vertebral arches, formation of an encephalocele (for<unk>  apertus), and dorsiflexion of the head in respect to the spine, can be precisely diagnosed as well as the severity and location established. Once established, further decisions can be made with regard to terminating the pregnancy or providing a plan of adequate postnatal care. Differential diagnosis Since many of the characteristics of<unk> , such as congenital retroflexion of the spine and fusion of the cervical vertebrae, are shared with other disorders, key differences are important to note. While anencephaly experiences a partial to total lack of the neurocranium,<unk>  does not. In anencephaly, the retroflexed head is not covered with skin while in<unk> , the retroflexed head is covered with skin entirely. Cervical vertebrae are malformed and reduced in<unk>  while they are almost normal in anencephaly. Even though KFS does experience malformed cervical vertebra due to failure of segmentation during early fetal development, there is not retroflexion of the head as seen in<unk> . While<unk>  clausus is fatal, KFS is not and can be surgically corrected. Therefore, it is crucial to correctly diagnose KFS and not mistake it for<unk>  clausus.
Iniencephaly
Klippel–Feil syndrome
Brachyphalangy
Microhydranencephaly
Oxycephaly
Hemihydranencephaly
Anencephaly
Hydranencephaly