Craniocervical junction anomalies are rare and their classification is considerably complex. Here we report two unusual cases of cervical spine dysmorphism presenting with the absence of posterior vertebral elements which are also accompanied with Wildervanck syndrome and hydrocephalus. The first case was a 17-year-old female who presented with short stature, broad neck, coarse voice, deafness as well as bilateral lateral gaze paresis. Cervical computerized tomography (CT) and magnetic resonance imaging (MRI) revealed the absence of posterior vertebral elements of cervical spine including partial agenesis of suboccipital bone, rotational deformity of cervical column, Chiari abnormality and cystic cavitation of cervical spinal cord. Additionally dextrocardia, which has not been defined as a feature of Wildervanck syndrome yet, was a marked feature of chest X-ray. The second case was a 32-year-old male presenting with complaints of gait disturbance, dysphonia, severe neck pain, short stature and scoliosis. Cervical X-ray, CT and MRI revealed severe basilar invagination, absence of dorsal elements of first two cervical vertebrae and hydrocephalus. Despite the absence of whole posterior cervical vertebral elements and even occipital bone, basilar invagination was not a predominant feature in the first case. We conclude that presence of a stable ligamentous structure only in anterior cervical column may have contributed to the strength of craniocervical junction and explains the absence of basilar invagination for Case 1.