Skull Anatomy PDF

Skull Reference :Snell clinical anatomy : pages 1486-1497  The Skull The skull is composed of several separate bones (22 bones) united at immobile joints called sutures.  The connective tissue between the bones is c...

Skull Reference :Snell clinical anatomy : pages 1486-1497  The Skull The skull is composed of several separate bones (22 bones) united at immobile joints called sutures.  The connective tissue between the bones is called a sutural ligament  Only one moveable bone, the mandible which is united to the skull by the mobile Temporomandibular Joint  The bones of the skull can be divided into: 1- Bones of the cranium (contain the brain) 2- Bones of the face The skull bones are made up of External and internal tables of compact bone separated by a layer of spongy bone called the diploic bones  The bones are covered on the outer and inner surfaces with periosteum.  The upper part of the cranium A) The cranium consists of the following bones two of which are paired : Frontal bone: 1 Parietal bones: 2 Occipital bone: 1 Temporal bones: 2 Sphenoid bone: 1 Ethmoid bone: 1 B) The facial bones consist of the following two of which are single: Zygomatic bones: 2 Maxillae: 2 Nasal bones: 2 Lacrimal bones: 2 Vomer: 1 Palatine bones: 2 Inferior conchae: 2 Mandible: 1  Anterior view Norma Frontalis  It is the anterior aspect of the skull Made of three parts 1-Upper part: Forehead; made of the frontal bone 2-Middle part: contains 3 caviteis;2 orbital & 1 nasal 3-Lower part: formed by the upper & lower jaws  The frontal bone, or forehead bone, makes the upper margins of the orbits. The superciliary arches are Elevated ridges above the orbital margins the supraorbital notch (or supraorbital foramen) is at the orbital margins -Medially, the frontal bone articulates with the frontal processes of the maxillae and with the nasal bones. Laterally, the frontal bone articulates with the zygomatic bone.  The orbital margins are bounded by the frontal bone superiorly, the zygomatic bone laterally, the maxilla inferiorly, and processes of the maxilla and frontal bone medially. The frontal bone contains two hollow spaces lined with mucous membrane, the frontal air sinuses, just above the orbital margins. The two nasal bones form the bridge of the nose. Their lower borders, with the maxillae, make the anterior nasal aperture. The nasal cavity is : divided into two by the bony nasal septum, which is largely formed by the vomer and also by the perpendicular plate of the ethmoid. The superior and middle conchae are shelves of bone that project into the nasal cavity from the ethmoid bone on each side. The inferior conchae are separate bones.  The two maxillae form the upper jaw, The two bones meet in the midline at the intermaxillary suture and form the lower margin of the nasal aperture. The infraorbital foramen perforates the maxilla below the orbit. The alveolar process projects downward and, together with the fellow of the opposite side, forms the alveolar arch, which carries the upper teeth. The zygomatic bone forms the prominence of the cheek and part of the lateral wall and floor of the orbital cavity, The zygomatic bone is perforated by two foramina for the zygomaticofacial and zygomaticotemporal nerves. The mandible, or lower jaw. 1- Frontal eminence: the most prominent areas on either side of the forehead 4-Glabela:an area above the root of the nose Between the 2 superciliary arches 5-Nasion:a point where the frontonasal & interanasal sutures meet 6-The nasal bones: form the roof of the nose Superior View of the Skull (Norma Verticalis) - Anteriorly the frontal bone articulates with the two parietal bones at the CORONAL SUTURE - The two parietal bones articulate in the midline at the SAGITTAL SUTURE. - posteriorly the LAMBDOID SUTURE can be seen. Posterior View of the Skull - You will see the posterior parts of the two Parietal bones with the intervening sagittal suture. - From Below, the parietal bones articulate with the squamous part of the occipital bone at the lambdoid suture. - On each side the occipital bone articulates with the temporal bone. - In the midline of the occipital bone is a roughened elevation called The external occipital protuberance which gives attachment to muscles and the ligamentum nuchae - On either side of the protuberance there are two superior nuchal lines extend laterally toward the temporal bone.and below there are two faint inferior nuchal lines.