Human Biology 2 Head & Neck Anatomy Skull Osteology 2024-2025 PDF

Human Biology 2 Head & Neck Anatomy Skull Osteology 2024-2025 Part 1 Dr.Basheer Muhammed Jafar Salman Lecturer- Oral Surgery B.D.S, M.Sc, MFDS RCS ( Edinburgh ) 1...

Human Biology 2 Head & Neck Anatomy Skull Osteology 2024-2025 Part 1 Dr.Basheer Muhammed Jafar Salman Lecturer- Oral Surgery B.D.S, M.Sc, MFDS RCS ( Edinburgh ) 1 Email: [email protected] References and further reading Martin Atkinson (2013): Anatomy For Dental Students. Fourth Edition, Oxford University Press. Lawrence E. Wineski (2018): Snell’s Clinical Anatomy by Regions. 10th Edition, Wolters Kluwer. Margaret J. Fehrenbach ( 2021 ): Illustrated Anatomy Of The Head and Neck. 6th Edition. Saunders Elsevier. 2 Objectives : 1- Outline the classification of the skull bones. 2- Identify the facial bones. 3- Identify the cranial bones. 4- Describe functions of the skull. 5- Identify the skull bones and landmark seen in: A- Anterior view of the skull B- Superior view of the skull C- Posterior view of the skull D- Lateral view of the skull E- Inferior view of the skull 3 Bones of the Skull - Classification They are divided into two groups: 1- Facial Bones = Facial Skeleton 2- Cranial Bones = Cranial Cavity = Braincase Facial Bones = 14 Bones Facial Skeleton - Zygomatic bones = 2 - Maxillae = 2 - Nasal bones = 2 Cranial Bones = 8 Bones - Lacrimal bones = 2 Cranial Cavity - Vomer = 1 - Palatine bones = 2 - Frontal bone = 1 - inferior conchae = 2 - Parietal bones = 2 - Mandible = 1 - Occipital bone = 1 - Temporal bones = 2 - sphenoid bone = 1 - Ethmoid bone = 1 Cranial cavity enclosing the brain 4  Vault Cranial Cavity ( Braincase) Consists of 2 parts: Upper part = The vault ( calvaria ) Lower part = The base of the skull ( cranial base ) Cranial base Cranial cavity Cranial 5 Vault base  The Vault ( calvaria ) - It forms the roof and side walls of the cranial cavity. - In section, it is made up of an outer and inner lamina (table) of compact Outer table bone separated by a layer of spongy bone called the diploe ( contains red marrow which has blood forming function) Inner table Diploe Outer table Vault Inner table Diploe 6 Bones of the Skull Facial Bones: Consist of the following bones: Zygomatic bones = 2 Maxillae =2 Nasal bones =2 Lacrimal bones =2 Lacrimal Nasal bone Vomer =1 bone Palatine bones =2 Inferior conchae =2 Zygomatic Mandible =1 bone Palatine bone Inferior Maxilla concha Vomer Mandible 7  Parietal Bones of the Skull bone Frontal bone The Cranial Bones: Consists of the following bones: Sphenid Frontal bone = 1 bone Parietal bones = 2 Occipital bone = 1 Temporal bones = 2 sphenoid bone = 1 Parietal bone Ethmoid bone = 1 Frontal bone Occipital bone Temporal bone Occipital bone Temporal bone 8 Sphenid bone Ethmoid bone Functions of the skull 1- It encloses and protect the brain. 2- Forms the skeleton of the upper parts of the alimentary and respiratory systems. 3- Provides protection for the organ of sight, hearing and smell. 4- It is intimately related to the teeth and soft tissues of the oral region. 9  Frontal bone Anterior view of the skull Bones seen in the anterior view: Frontal bone. Maxillary bones zygomatic bones. Nasal bone Mandible. Nasal bones. Vomer. Vomer Inferior concha. Zygoma Maxilla Inferior concha Mandible 10 Anterior view of the skull Frontal bone Landmarks: Superciliary arch 1- The two orbital apertures and anterior nasal aperture (piriform Glabelle aperture). 2- The frontal bone forms the Supraorbital upper margin of the orbit margin (supraorbital margin). 3- Superciliary arch is a smooth elevation above the supraorbital margin medially, it forms the eyebrow ridge in the living subject. 4- Glabella: a slight elevated area above the bridge of the nose. 11 Anterior view of the skull Landmarks: Frontal bone 5- Supraorbital notch or foramen in the superior orbital margin, Supraorbital notch related to the frontal bone. 6- Infraorbital foramen in the Infraorbital foramen lower margin of the orbit, related to the maxilla. 7- Mental foramen in the mandible below the apices of the premolars. Maxilla Mandible 12 Mental foramen Anterior view of the skull Landmarks: 8- The two nasal bones form the bridge of the nose. 9- Anterior nasal aperture Nasal bone Nasal bone formed by the lower border of the nasal bones with the maxillae. 10- The nasal cavity is divided into two cavities by the nasal septum. Zygoma 11- The zygomatic bone forms the prominence of the cheek and Maxilla part of the lateral wall and floor of the orbit. Nasal septum 13 Superior view of the skull Frontal bone Bones seen in the superior view: Coronal suture Frontal bone. Parietal bones. Occipital bone. Parietal bone Landmarks: 1- Sagittal suture: in the median plane between the two parietal bones. 2- Coronal suture: between the frontal & parietal bone. Sagittal suture 3- Lambdoid suture: between occipital and parietal bones. 4- Parietal foramen: close to the Parietal foramen sagittal suture on the posterior part of the parietal bone. Lambdoid suture 14 Occipital bone  Superior view of the skull Landmarks: 5- Frontal ( metopic ) suture: In the immature skulls, a suture presents in the median plane of the frontal bone dividing it into right and left halves. In the majority of individuals, it fuses during early childhood but in a few it persists into adult life. Metopic suture 15 Superior view of the skull Landmarks: Bregma 6- Bregma: Is the site of junction of the coronal and sagittal suture. It corresponds to the anterior fontanelle ( soft spot ) on the fetal skull. Lambda 7- Lambda: Is the site of junction of the lambdoid and sagittal suture. It corresponds to the posterior fontanelle ( soft spot ) on the fetal skull. 16 Lateral view of the skull Parietal bone Frontal Bones seen in the lateral bone view: Frontal bone Sphenoid bone Parietal bones Zygoma Occipital bone Temporal bone Lacrimal bone Sphenoid bone Zygoma Maxilla Lacrimal bone Nasal Nasal bone bone Occipital bone Mandible Temporal bone 17 maxilla Mandible Lateral view of the skull Temporal Landmarks: lines 1- Temporal lines: ( Superior & inferior ) They begin as a single line anteriorly, the two lines diverge as they pass posteriorly and they arch across the frontal and parietal bone. 2- Temporal fossa: It is an area on the lateral wall of the skull bounded by superior temporal line. Temporal fossa Note: Infratemporal fossa located Infratemporal fossa below temporal fossa deep to the ramus of the mandible. 18 Lateral view of the skull Landmarks: Parietal 3- Pterion: Frontal bone bone It is an irregular H shaped arrangement of sutures where the frontal, sphenoid, parietal and temporal bone meet. This area is crossed on its internal surface by the anterior branchs of middle meningeal artery and vein. Pterion Temporal bone Sphenoid bone 19 Pterion Clinical significance. Trauma to the pterion can lead to tearing of the middle meningeal vessels. Middle meningeal artery The middle meningeal vessels lie between the dura mater and the periosteum of the internal aspect of the skull. The build up of blood in this space may lead to: Compression of the brain tissue. Decrease level of consciousness. Untreated hemorrhage may cause death in a few hours. Middle meningeal 20 vessels Lateral view of the skull Landmarks: 4- Temporo-mandibular joint (TMJ): It is an articulation between the mandible and the temporal bone. 5- External acoustic meatus: It is a bony canal that leads to the middle ear. Zygomatic arch Temporal bone 6- Mastoid process: It is a bony prominence located behind the external acoustic meatus ( part of the temporal bone ) 7- Styloid process: Mastoid It is a long slender process projecting downwards from the temporal bone. 8- Zygomatic arch: EAM Bony arch formed by articulation of temporal and zygomatic bone. Mandible Styloid process 21 Posterior view of the skull Parietal bone Occipital Bones seen in the posterior bone view: Occipital bone: Mainly the squamous part of occipital bone. Lambdoid suture Parietal bones. Landmarks: 1- Lambdoid suture: Between parietal bones and the occipital bone. 22 Posterior view of the skull Occipital bone Landmarks: 2- External occipital crest: Supreme nuchal line It begins at the posterior margin of S. Nuchal the foramen magnum and ends at a line prominence called External occipital protuberance. (Inion is the most prominent EOP projection of the protuberance and it is the site for muscle and EOC ligament attachment. Inion 3- Superior Nuchal lines: Run laterally from the protuberance toward the mastoid EOP process of temporal bone. 4- Inferior nuchal line: EOC I. Nuchal below superior ones. line Foramen 5- supreme nuchal lines: magnum 23 above superior ones. Inferior view of the skull maxilla Bones seen in the inferior view: Palatine bone Maxilla Sphenoid bone Palatine bone Vomer Sphenoid bone Temporal Vomer bone Temporal bone Occipital bone Occipital 24 bone  Maxilla Inferior view of the skull Palatine process Parts of bones seen in the inferior view: Palatine bone Sphenoid bone Maxilla Horizontal plate Body - Palatine process of maxilla. Vomer Palatine bone Greater wing - Horizontal plate. Vomer Pterygoid plates Sphenoid bone: Temporal bone - Body - Greater wings Squamous part - Pterygoid plates Tympanic plate Temporal bone - Petrous part Mastoid process - Styloid process Styloid process - Mastoid process - Tympanic plate Petrous part Condylar part - Squamous part Occipital bone Occipital bone: Basilar part - Squamous part - Basilar part Squamous part 25 - Condylar parts  Review Questions Identify the labeled bones & landmarks. A J I B A D H C B E G C D F E F 27