Foraminacephale, as a pachycephalosaurid, was a small, bipedal herbivore with a thickened dome on its skull.
In 2016, Gregory S. Paul estimated its length at 1.5 metres (4.9 ft), its weight at 10 kilograms (22 lb).
In Foraminacephale, the top surface of the dome is punctuated by many small pits, the eponymous foramina; the dome itself consists of a large, central lobe with a sloped frontal half, and two smaller lateral lobes at the front.
The squamosal bone forms a tall bar of completely smooth bone underneath the dome, save for six bony nodes that line the bottom edge of the dome and an additional "corner" node just below.
These features differentiate Foraminacephale from all other pachycephalosaurids.

Unlike Stegoceras, Hanssuesia, and Colepiocephale, the parietal bone of Foraminacephale (which constitutes the back part of the dome) projects backwards and downwards over the base of the skull.
Two traits also differentiate Foraminacephale from Sphaerotholus and Prenocephale: there are prominent grooves between the central lobe and the lateral lobes, and the opening of the temporal bone is slit-like.
Foraminacephale, as a pachycephalosaurid, was a small, bipedal herbivore with a thickened dome on its skull. In 2016, Gregory S. Paul estimated its length at 1.5 metres (4.9 ft), its weight at 10 kilograms (22 lb). In Foraminacephale, the top surface of the dome is punctuated by many small pits, the eponymous foramina; the dome itself consists of a large, central lobe with a sloped frontal half, and two smaller lateral lobes at the front. The squamosal bone forms a tall bar of completely smooth bone underneath the dome, save for six bony nodes that line the bottom edge of the dome and an additional "corner" node just below. These features differentiate Foraminacephale from all other pachycephalosaurids.
Unlike Stegoceras, Hanssuesia, and Colepiocephale, the parietal bone of Foraminacephale (which constitutes the back part of the dome) projects backwards and downwards over the base of the skull. Two traits also differentiate Foraminacephale from Sphaerotholus and Prenocephale: there are prominent grooves between the central lobe and the lateral lobes, and the opening of the temporal bone is slit-like.
Foraminacephale