Caput is oedema and bruising of the scalp, commonly associated with ventouse deliveries. This resolves within a few days and can cross suture lines. Whilst not clearly captured here, it should be possible to demonstrate pitting oedema if there is any uncertainty as to the diagnosis.
Another, rarer, differential diagnosis is a Subgaleal haemorrhage: a bleed between the galea aponeurosis and periosteum that gives rise to a boggy appearance and, in severe cases, can lead to hypovolaemia. These may be associated with a coagulopathy in the infant.