[A complex of skull base and cervical spine anomalies and Chiari type I malformation].

To study a relationship between the skull base and cervical spine anomalies and Chiari type I malformation (CMI), 364 patients with CMI were examined using craniography and magnetic resonance imaging of the brain and spinal cord. To reveal bone anomalies and CMI, morphometric data analysis was performed. The control group consisted of 120 patients without central nervous system pathology, cranial and cervical spine anomalies. The data obtained allowed dividing the skull base and cervical spine anomalies identified in the CMI patients into 3 groups: 1) primary anomalies (basilar invagination, platybasia, atlantal assimilation) predisposing to CMI development; frequent occurrence and reliable interrelation between these anomalies and CMI severity were found that confirmed the results reported in the literature on their key role in a small size of posterior cranial fossa; 2) combined with CMI bone anomalies, which do not influence CMI development (Klippel--Feil and Kimmerle anomalies); 3) secondary skull base and cervical spine deformations formed as a result of CMI impact (foramen magnum and cervical canal enlargement).