This form of craniosynostosis (“lamboid synostosis”) is caused by fusion of the bones on the side and the back of the head. It results in a flattened area on the side of the synostosis; the back of the head shifts to the unaffected side; and the area near the ear (mastoid process) may bulge. It is very rare and can be confused with deformational posterior plagiocephaly.
Learn more about Synostic posterior plagiocephaly in Related Articles: About Craniosynostosis