He believed that the sulcus would be in the area of the lambdoid structure. Most commonly these are found in the course of the lambdoid suture. Another one is Lambdoid synostosis (posterior plagiocephaly). The sagittal crest is not present, while the lambdoid crest is well developed. The lambdoid suture joins the occipital bone to the parietal bones. Further back on the braincase, the lambdoid crest is poorly developed. Further back on the braincase, the lambdoid crest is also prominent. Further back on the braincase, the lambdoid crest is also poorly developed. Further back on the braincase, the lambdoid crest (another such crest) is also prominent.