As the result of injury sustained during protracted labour, hæmatomata may develop beneath the aponeurosis of the occipito-frontalis or underneath the pericranium, the latter being the more common situation. The right side of the head is the more frequently involved, and the parietal region is the part usually affected. Occasionally these hæmatomata are bilateral and symmetrical.
The two varieties of cephalhæmatoma—subaponeurotic and subpericranial—possess certain peculiarities that aid materially in their differential diagnosis.
Subaponeurotic hæmatomata.
The blood, though spreading widely throughout the subaponeurotic space, tends to gravitate towards the lower confines of that space, and, from the position assumed by the patient, is most evident in the occipital region. The presence of the blood is evidenced by œdema, doughiness, and ecchymosis.
Subpericranial hæmatomata.
The blood is confined to the region of the particular bone affected, usually the right parietal bone. This is due to the fact that the pericranium blends at the margins of the bone with the tissue intervening between that bone and the neighbouring parts of the skull.
Subpericranial hæmatomata present further peculiarities. The tumour is usually more or less circular in outline, and fluctuates freely. It may arise immediately after the birth of the child, but, more commonly, some two or three days elapse before attention is drawn to its existence. Within a few days clotting occurs at the periphery of the hæmatoma with the formation of a circumferential ridge. The central portion of the clot remains soft but tense, so much so that firm pressure is required before the examining finger is enabled to feel the underlying bone. These cephalhæmatomata are not infrequently mistaken for depressed fractures, but no difficulty should be experienced if the existence of the circumferential ridge be appreciated and if the underlying bone can be felt at the centre of the tumour. In cases of doubt the blood should be drawn off by aspiration and the swelling again examined.
For differential diagnosis, see [p. 57].
Treatment.
The less extensive hæmatomata require no active surgical treatment, the absorption of the clot being aided by protection of the part and by cooling lotions.