The skull is composed of 23 irregular bones, including 15 facial cranial bones and 8 cerebral cranial bones. The facial skull encloses the orbits, nasal cavity and oral cavity, one on each side, including the maxilla, nasal bone, lacrimal bone, zygomatic bone, palatine bone, inferior turbinate bone, plow bone, mandible and free hyoid bone; the cerebral skull consists of the skull cap and skull base, the skull cap includes the frontal bone, parietal bone, occipital bone, temporal bone and part of the zygomatic bone and large wing of the pterygoid bone. The skull cap includes the frontal bone, parietal bone, occipital bone, temporal bone, and part of the zygomatic bone and the large wing of the pterygoid bone, which are connected by coronal, sagittal, herringbone and squamous sutures. Together they form the anterior, middle, and posterior cranial fossa structures.