Which condition involves bleeding between the periosteum and the skull?

The correct choice refers to cephalohematoma, which occurs when there is bleeding between the periosteum and the skull. This condition typically arises as a result of birth trauma during delivery, particularly with the use of forceps or vacuum extraction. The bleeding can result in a raised area on the baby's head that feels firm and may take several weeks to resolve as the blood gradually reabsorbs.

In the context of neonatal conditions, caput succedaneum involves swelling of the soft tissues of the head that crosses suture lines due to pressure during delivery, but it is not a hematoma like cephalohematoma. Erythema toxicum is a benign rash seen in newborns, while Mongolian spots are flat, blue or purple marks that appear on the skin and are not related to bleeding. These distinctions are essential for understanding the different types of conditions and their implications for care in newborns.