Ribs

Supernumerary ribs may develop in the cervical region (cervical ribs). These ribs may compress nerves (brachial plexus) and blood vessels (subclavian artery).

Skull

The two frontal bones normally fuse together around age six. Lack of fusion causes a metopic suture.
The premature closure of one or more sutures of the skull bones leads to a deformity of the head (craniosynostosis). This anomaly is inherited in an autosomal dominant mode.
In cleidocranial dysostosis, also an autosomal dominant anomaly, ossification is generally retarded. The clavicule is either missing or underdeveloped. Facial bones and teeth are also underdeveloped. This may be combined with other skeletal malformations.
Assimilation of the atlas (the first cervical vertebra) is a condition in which the anterior part of the arch of the atlas fuses with the occipital bone. In synostosis of the atlas the atlas and the occipital bone fuse completely.