Skull development refers to the process by which the skull forms and matures during an organism's growth. In humans, this process begins in the womb, where the skull is made up of several bones that are initially separated by flexible joints called sutures. These sutures allow for growth and expansion of the skull as the brain develops, particularly during infancy and early childhood. As a child grows, the bones of the skull gradually fuse together, providing a protective structure for the brain. By the time a person reaches adulthood, the skull is fully formed, with the sutures closed. Proper skull development is crucial for protecting the brain and supporting facial structure, and any abnormalities can lead to conditions such as craniosynostosis.