The suture is frequently convoluted, forming a tight union that prevents most movement between the bones. In adults, the skull bones are closely opposed and fibrous connective tissue fills the narrow gap between the bones. The fibrous connective tissue found at a suture (“to bind or sew”) strongly unites the adjacent skull bones and thus helps to protect the brain and form the face. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.Īll the bones of the skull, except for the mandible, are joined to each other by a fibrous joint called a suture. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (a) Sutures join most bones of the skull. Fibrous joints form strong connections between bones. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. At a syndesmosis joint, the bones are more widely separated but are held together by a narrow band of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. A suture is the narrow fibrous joint found between most bones of the skull. The gap between the bones may be narrow or wide. Give an example of each type of fibrous jointĪt a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 1).Distinguish between a suture, syndesmosis, and gomphosis.Describe the structural features of fibrous joints.The occipital condyles on either side of the foramen magnum articulate with the first vertebra (C1) of the spine to permit up-and-down movement of the head.\) The spinal cord passes through the largest hole, called the foramen magnum, in the base of the cranium to join the brain. Small holes in the skull bones, called foraminae, enable blood vessels, such as the carotid arteries and nerves, to enter and leave the skull. The two bones of the mandible form the lower jaw, and both the maxillae and mandible anchor the teeth. The vomer is a single bone that makes up part of the nasal septum, which divides the nostrils. Each of the following facial bones are paired: the maxillae form the upper jaw and front of the hard palate the zygomatic bones form the cheeks the nasal bones form the bridge of the nose the lacrimal bones form part of the orbit, or eye socket the palatine bones form the rear of the hard palate and the inferior nasal conchae divide the nasal cavity. The 14 facial bones provide structure for the face and form the openings through which food, water, and air enter the body. By 18-24 months, the skull sutures typically have formed and the fontanels have disappeared. Fontanels allow the skull to be compressed slightly during birth and accommodate growth of the brain during early infancy. In newborns, the skull bones are not completely fused, but linked by soft, fibrous membranes called fontanels. The mandible, or lower jaw, is the only bone in the skull that moves, and it allows the mouth to open and close. The sutures lock the edges of the skull bones together, like pieces in a puzzle, to form a structure that is both rigid and strong. In adults, all but one of the 22 bones of the skull are fused together by immovable joints called sutures. The occipital bone forms the back of the skull. The ethmoid bone, located at the roof of the nose between the eye sockets, separates the nasal cavity from the brain. The butterfly-shaped sphenoid bone is located at the base of the skull. The two parietal bones form the upper sides of the skull the two temporal bones form the lower sides. They include the frontal, parietal, occipital, temporal, sphenoid and ethmoid bones. The eight bones of the cranium form the “vault” that encloses the brain. The important elements of the human skull include: The Cranium The bones of the skull and face are designed to protect the brain, provide structure for the face, and form the openings through which food, water, and air enter the body.ĭid you know that the skull actually consists of 22 bones? Of these bones, eight make up surround and protect the brain, and the remaining 14 form the underlying structure of the face.
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