2The Skull The Skull (Cranium): The skull is composed of several separate bones united by sutures except for the mandibule that is united to the skull by temporo-mandibular joint.
3The Function of SkullThe main function of the skull is that encloses and protect the brain and meninges in its cavity and the special senses (eyes and ears) within the skull bones or cavities bounded by them.
4Divisions of Skull The skull (Cranium) can be divided into: 1- Neurocranium (sometimes called cranium)2- Viscerocranium (Facial Skeleton)The neurocranium is subdivided into1- Upper part the Vault (Calvaria or skull cap)2- Lower part called the base of the skull (basicranium).
5Skull Bone /SutureThe skull bones are made up of external and internal layers of compact bone covered by periosteum and separated by a layer of spongy bone called the diplo.
6SuturesSutures:The sutures are fibrous joints uniting the bones of the skull.Sutures Names? Examples?1- The Coronal suture: between frontal and the two parietal bones.(bregma/Lambda)2- The Sagittal suture: between 2 parietal bones in midline.3- The Lambdoid suture: between occipital bones posteriorly and the two parietal bones. Along the lambdoid suture small islands of bone (sutural bones or wormian bones)4- The Metopic suture: separate the frontal bone into two halves (persist in 8% of people.)
8Neonate Skull Anterior fontanelle at the bregma (18 months) Posterior fontanelle at the Lambda site (3 months)Sphenoidal fontanelleMastoid fontanelle
9Skull Landmarks: Pterion: Junction of the greater wing of the sphenoid, squamous temporal, frontal, and parietal bones; overlies course of anterior division of middle meningeal arteryLambda:Point on calvaria at junction of lambdoid and sagittal suturesBregma:Point on calvaria at junction of coronal and sagittal suturesVertex:Superior point of neurocranium, when the skull is in the anatomical position.Asterion:Star shaped; located at junction of three sutures: parietomastoid, occipitomastoid, and lambdoidGlabella:Smooth prominence; most marked in males; on the frontal bones superior to root of nose; most anterior projecting part of foreheadInion:Most prominent point of external occipital protuberanceNasion:Point on cranium where frontonasal and internasal sutures meet
10Frontal Bone: (Forehead Bone) Forms: Forehead, superior orbital margin and orbital roof.Contents: frontal sinuses.Landmarks: Superciliary arches. Medially, (Glabella) The arches are more prominent in males.Foramens: Medial 1/3 = Supraorbital notch or foramen. Transmits?Articulations?
12The Nasal Bone Forms: nasal bridge, sup. Border of Piriform aperture Contents:Landmarks:Foramens: Nasal foramen.Articulations: internasal suture, frontonasal suture
13Zygomatic BoneForms: prominence of a cheek, floor & lateral wall of the orbit, the walls of the temporal and infratemporal fossae, and zygomatic archContents:No SinusLandmarks: ?Foramens: zygomaticofacial foramen?Articulations:?
14Lacrimal BoneForms: Post crest of Lacrimal canal, medial wall of orbitContents: smallest?Landmarks: Post. Lacrimal CrestForamens: nasolacrimal canalArticulations:?
15The Anterior Orbital Opening Superiorly by frontal boneInferiorly by Maxillary boneLaterally by frontal process of Zygomatic bone and Zygomatic process of frontal boneMedially by frontal process of Maxillary bone and Maxillary process of Frontal bone.
17The Mandible Forms: the lower jaw and supports the teeth Contents: Horizontal body of mandibleand Vertical ramus of mandibleLandmarks: mental protuberance (Chin) , mental tubercles.Foramens: mental foramen:The Ramus Has :1- Condylar Process2- Coronoid Process
18Vomer Forms: posteroinferior part of the nasal septum Articulations: Superiorly - sphenoid bone and sphenoidal processes of the palatine bones.Inferiorly - nasal crests of the maxilla and palatine bones.Anteriorly - perpendicular plate of the ethmoid bone and the nasal septal cartilage.Posteriorly – No ??
19Ethmoid BoneForms: medial walls of the orbit, nasal septum and the roof & lateral walls of the nasal cavity.Contents: 2 plates and 2 labryinthsLandmarks: Crista Galli,Foramens: ?Articulations:?
22Parietal Bone Forms: cranial roof and sides Contents:No Landmarks: ? MarkingsForamens: Parietal foramenArticulations:1- Medially- Parietal bone in the midline at ? suture2- Anteriorly- frontal bone at ? suture3- Posteriorly- occipital bone at ? suture4- Laterally- Temporal bone at parieto-temporal suture (squamous part anteriorly and mastoid part posteriorly)
23Occipital Bone Forms: Base of the skull Contents: 4 parts Landmarks: External occipital protunerance, sup & inf nuchal line, lat condyles, occipital crest, pharyngeal tubercleForamens: Foramen Magnum, Hypoglossal, condylar canal, jugularArticulations: ?
24Palatine Bone Forms: roof of mouth, nasal wall Contents: 2 plates (L shape) 3 processesLandmarks:Foramens: greater and lesser palatine foramensArticulations: interpalatine suture, Maxillary bone?,
25Sphenoid Bone Forms: orbital wall, temporal fossa wall, base of skull Contents: sphenoid sinus4 wings (lesser, greater), body, 2 Pterygoid Processes.Landmarks:Foramens: G. wing = foramen ovale & spinosumArticulations: