The fontanel is the soft spot on top of Lucy’s head. Everyone in the family is afraid to press on it, except her brother Jimmy. The fontanel is part of a fascinating skeletal process. In order to facilitate the passage of the baby’s head through the delivery canal, the skull is made up of several bones that are attached loosely together; after birth, this design allows the brain and skull to grow. Between these bones there are actually two soft spots: a large one on top and a less obvious one in the back. The top one varies in size from large to almost nonexistent. Lucy’s soft spot becomes more noticeable when she cries, which increases pressure on her brain and makes her spot bulge. If she gets a fever, you can see the fontanel pulsate as her blood flow increases. When Lucy sleeps, pressure diminishes, and it becomes slightly depressed.
Fontanels close at different times. The rear one usually disappears by her third month, and the one on top remains more or less until her first birthday. Generally, the larger the spot, the longer it takes to close. As far as the fragility of the fontanel, you can let Jimmy touch it; a strong membrane protects this mysterious area, and incidental pressure won’t hurt.