The prefixes "cephal" and "cephalo" refer to the head, and "hematoma" is the medical term for a collection of blood. Cephalohematoma, therefore, is a collection of blood in the area of the head, specifically under a structure called the periosteum. This is a strong, white fibrous material that covers the bones, including the cranium, commonly known as the skull. Nerves and blood vessels pass through the periosteum as they leave and enter the actual bone. When blood collects under this membrane, the condition is called cephalohematoma in medical terminology.

Cephalohematoma can have the appearance of a soft swelling just under what appears to be the scalp and is outlined by borders. It often is described as a bulge in the scalp. If palpated, it can feel like a small balloon containing a liquid such as water. A large cephalohematoma, when palpated, might feel firm instead of mushy.

Minor injury during labor or delivery of a baby can cause this condition. If a baby's head is large enough to cause pressure to be exerted on it as it passes through the pelvic bones of the mother, tearing of the periosteum can occur. The tearing of the tiny blood vessels in this membrane results in hemorrhage or bleeding, which causes blood to collect under the structure. Cephalohematoma occurs more commonly when forceps are used during delivery. Sometimes, it also is seen in the delivery of the babies of first-time mothers.

Although this condition can involve a cranial fracture, it usually heals without medical intervention. A physician usually will refrain from inserting a needle into the hematoma because of the risk of infection. Generally, the blood is broken down into its components and reabsorbed into the newborn's system, where it will either be recycled or discarded. Bilirubin is one of the components that, if the hematoma is large, might lead to hyperbilirubinemia or jaundice of the baby, but this rarely is seen, as are deposits of the mineral calcium in the collection of blood. Parents who have a baby with cephalohematoma are advised to consult a doctor concerning any bulge present on their baby's skull to be sure there are no life-threatening injuries to the child.

Calcification and hardening usually follow the formation of the hematoma within a period of two or three months. Generally, there is no need to be concerned about scarring, because the swelling and any traces of the collection of blood hardly ever are seen even with the use of X-ray technology. The baby should continue to develop without any health problems related to cephalohematoma.