Question

why does the skull have fixed joints

Answer 1

In utero, the articulations between our skull bones are not yet as hard (in fact these are the baby's soft spots) as in adults - the bones are separated by this tissue which allows for a number of things: (1) skulls can deform during birth, allowing the baby to go through labor with less effort, and therefore (2) provoke less trauma to the mother's birth canal. (3) more room to grow as a child. Most of these soft spots disappear after birth due to pressures from the birth canal.



(this is a drawing of a newborn's skull)
It is somewhat common during birth for the skull bones to overlap due to trauma associated with childbirth - otherwise this would cause a skull fracture and cause much more damage to the brain.

Answer 2

these joints are called fixed joints because they do not move. fiborous joint have no joint cavity and are connected via fiborous connective tissue. the skull bones are connected by fiborous joints