The parts of these bones that lie inferior to the brain are considered to be a part of the skull base (mentioned below). These bones protect the brain superiorly, but also provide an anchor for important muscles of facial expression and eye movement. The calvarium, also known as the roof or skull cap, consists of three bones: The fontanelles undergo complete ossification within 9 – 18 months from birth.Ĭlinical relevance: Fontanelle abnormalitiesĪn enlarged anterior fontanelle can be due to endocrine pathologies like congenital hypothyroidism.Ī bulging anterior or posterior fontanelle may suggest raised intracranial pressure, which may occur in hydrocephalus.Ī sunken anterior or posterior fontanelle may suggest dehydration. Posterior fontanelle: the soft region on the back of the infant’s head.Anterior fontanelle: the soft region on the front of the infant’s head.Base: the sphenoid, ethmoid, occipital and temporal bones tend to grow slightly laterīy week 37, the cartilaginous frame for the skull is almost entirely replaced by bone, and only two relatively small cartilaginous structures remain:.

Calvarium (roof): the frontal, occipital and parietal bones tend to grow slightly earlier.This process occurs at different rates in two different regions of the skull: A cartilaginous mould begins to grow and is slowly replaced by bone in a process called intramembranous ossification. The skull begins to form prior to week 12 of embryogenesis. You might also be interested in our Anatomy Flashcard Collection which contains over 2000 anatomy flashcards in addition to advanced features such as spaced repetition.

Skull and neck bones