الفهرس 
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Abstract
By definition, the craniovertebral junction includes the foramen magnum, the atlas, and the axis vertebrae. The occipito atlantoaxial joints are complex, both anatomically and kinematically. Anatomically, there are two occipito¬atlantal articulations. There are four atlantoaxial joints wi th a common synov i all in i ng. These joi nts funct i on as a ball-and-socket joint. Flexion-extension and lateral bending occurs at the occipitoatlantal joint, flexion-extension and axial rotation occurs at the atlanto axial joint. The pathology of craniovertebral junction anomal ies and malformations is extensive. According to the -s t u dy of menezes and Van Gilder, 1990, these abnormal ities could be classified into separate etiologies for congenital, developmental and acquired disorders. Congenital anomalies are attributed to malformations of either the occipital bone, atlas or axis. Those include manifestations of occipital vertebrae, basilar invagination, condylar hypoplasia, assimilation of the atlas, atlanto-axial fusion and irregular segmentation, os o don t 0 ide u man dot her con g e nit a 1 a nom ali e s 0 f the od 0 n t 0 i d . Developmental and acquired abnormal ities of the craniovertebral junction include abnormal ities at the secondary basilar invagination and atlanto-axial instability as in rheumatoid arthritis, infections, foramen magnum as in foraminal stenosis and traumatic