Front piece of antique medical skull.
This is an unusual item. It is the front of an old medical skull. It looks like the skull would have had a detachable cranium which would account for the smooth cut across the frontal bone on the forehead. The rest of the frontal is still in place together with the facial bones as can be seen in the photos. The teeth are all absent now and there is some damage to the left zygomatic bone.
Judging by the grey colour and good patina, I think that this is from quite an early medical skull.