Final answer:
The swelling of a baby's head that extends from above the left ear to 2 cm below the top of the skull is known as cephalohematoma, which is a collection of blood under the skin that does not cross suture lines of the skull bones.
Step-by-step explanation:
The term used to describe the swelling of a baby's head that extends from above the left ear to 2 cm below the top of the skull is cephalohematoma. Cephalohematoma is a collection of blood between the skull bone and its fibrous covering, typically developing over the first day of life and not crossing suture lines. Unlike caput succedaneum, which can extend across the midline and over suture lines, cephalohematoma is confined to one cranial bone.
The fontanelles are the soft spots on an infant's head, represented by broad areas of fibrous connective tissue that form fibrous joints between the bones of the skull. The largest of these is the anterior or frontal fontanel, situated at the top front part of the skull. It, along with the smaller posterior or occipital fontanel, located at the back of the head, allows the baby's head to change shape to pass through the birth canal during delivery, a process known as molding.