Skull

The skull is located around the brain that the bone structure is really strong, so it can protect the brain. For the average adults, the skull is composed of twenty-three bone structures. However the picture of skull expresses the dangerous substance or it is used as the symbol of horror, because the skull reminds everyone of the dead body so that could scare people by how it looks. The skull is made of four parts: neurocranium, facial skeleton, ossicle, and hyoid bone. The skull protects the brain and it provides a space for sensory system like nose, ear, eyes, and mouth. Also there is an entrance to the body for respiratory system. Where the teeth are located helps to chew and bite. Except for the temporomandibular joint, the skull is connected to a fibrous joint so between bone and bone there cannot be joint movement.

History
Scientists know the progress of skulls by studying fossils. From 500 million years ago, no creature had a skull. A long time ago, skulls have changed from old collection of fossils to be reinforced. It is really important to know skull’s age and its characteristics, this information provides important leads about where the creatures are from and is related to the other animals like the animals that have the tiny teeth and mammals that have a long nose.

Cranial Bones
It is surrounded by the brain of the skull known as the cranium and cranial bones have six bones: Frontal bone, Two parietal bones, Two temporal bones, Occipital bone, Ethmoid bone, and Sphenoid bone. Cranial Bones provide a strong wall around the brain, with openings for nerves and blood vessels. The occipital bone, which is the part located at the top of the skull, has the foramen magnum so the spinal cord can go through the hole to attach to the brain. The occipital bone forms the atlanto-occipital joint with the atlas. The frontal, ethmoid, and sphenoid bone has small spaces it is called paranasal sinuses. This reduces the weight of the bones and increase the volume of the voice during presentation, conference, speech, and singing.

Facial Bones
There are 14 bones that help or support the muscles and organs of the face and are known as human's facial bones. Facial Bones eight bones: Mandible, two maxillae, vomer, two palatine bones, Two nasal bones, two zygomatic bones, two nasal conchae, and two lacrimal bones. The only bones that are able to move in the facial bone of the skull are the mandible and jaw. The low teeth are rooted in the mandible and the upper teeth are rooted in the two maxillae. The maxillae also has paranasal sinuses like the frontal, ethmoid, and sphenoid bones of the facial bones. Facial bones are neural crest like the cranium and teeth. Adrenal medulla is from the facial bones. People's facial bones are made up of cartilage and it becomes stronger by endochondral ossification. Other animals such as chondrichthyes their bones do not get stronger because they have the cartilaginous vertebra.

Video
The video is talking about the cranial bones and facial bones of the skull. it also talks about the parts of the skull and how the parts can protect the important things like blood vessels or the brain. Nc5IRj3OJhE