Congenital absence of a pedicle in a cervical vertebra.

The importance of agenesis of a pedicle lies in its resemblance to a destructive lesion of the pedicle or to an expanding lesion in an intervertebral foramen. The correct diagnosis can be made roentgenologically by demonstrating a widened intervertebral foramen at the level of an absent pedicle with posterior displacement of the maldeveloped lateral mass. Two cases of agenesis of a pedicle in a cervical vertebra are presented.