part of part of Homo sapiens occipital bone surface groove groove for transverse sinus of squamous part of occipital bone 2026-03-19T00:00:00Z A surface groove curving horizontally across the internal surface of the squamous part of the occipital bone, one on each side, lodging the transverse sinus as it passes from the confluence of sinuses toward the sigmoid sinus. David Osumi-Sutherland