Osteology of facial skeleton

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  1. 1. Osteology of facial skeleton By Dr. Kalpajyoti Bhattacharjee Dept of oral pathology
  2. 2. CONTENTS Introduction Classification Skull Calvarium- paired and unpaired bones Norma ventricalis Norma occipitalis Norma lateralis Norma frontalis Norma basalis Interior of the skull Facial skeletons
  3. 3. INTRODUCTION Bone is the hard part of the body providing framework to it Bone acts as levers for muscles and therefore help in the movements of the body Bone provides protection to the visceral organs like brain, lungs and heart Bone is the site of blood formation Plays an important role in the immune responses of body Store house of calcium and phosphorus
  4. 4. Study of bones-osteology There are 206 bones in our body Skull has 22 bones Skull is the skeleton of head Cranium- skull minus mandible Calvaria is upper part of cranium also called brain box Facial skeleton is skull minus calvarium
  5. 5. 22 bones join to form the skull 8 pairs and 6 individuals Divided into neurocranium and viscerocranium Sometimes sutural bones present
  6. 6. CLASSIFICATION According to shape Long bones ( eg: humerus, radius) Short bones (eg: carpal and tarsal bones) Flat bones (eg: vault of the skull, ribs ) Irregular bones (eg: Vertebra, hip bone ) Pneumatic bones (eg: maxilla, sphenoid ) Sesamoid bones (eg: patella)
  7. 7. Developmental classification Intramembranous or mesenchymal ossification. eg: bones of the vault of skull and facial bones Intracartilaginous or endochondral ossification. eg: bones of limbs, vertebral column and thoracic cage. Membrano-cartilaginous bones. eg: clavicle, mandible. Microscopic structure Mature bone. Immature bone
  8. 8. Neurocranium Viscerocranium The neurocranium covers the brain The viscerocranium comprises the facial bones
  9. 9. SKULL Cranium: Consists of 8 bones (1) Frontal Bone (2) Temporal Bones (2) Parietal Bones (1) Occipital Bone (1) Sphenoid Bone (1) Ethmoid Bone Face: Consists of 14 bones (2) Maxilla (2) Zygomatic bones (2) Lacrimal bones (2) Palatine bones (2) Nasal bones (2) Nasal conchae (1) Vomer (1) Mandible
  10. 10. CALVARIUM The bones which constitute the calvaria or brain case are Unpaired bones a.Frontal bone b.Occipital bone c.Sphenoid bone d.Ethmoid bone Paired bones- a.Parietal, b.Temporal
  11. 11. NORMA VERTICALIS Oval in shape Wider posteriorly than anteriorly. Bones seen in norma verticalis: 1) upper part of frontal bone anteriorly. 2) uppermost part of occipital bone posteriorly. 3) A parietal bone on each side.
  13. 13. Sutures seen are: Coronal suture: placed between the frontal bone and the 2 parietal bone. Sagittal suture: placed in the median place between the 2 parietal bone. Lambdoid suture: posteriorly between the occipital and the 2 parietal bone. Metopic (latin forehead) suture: occasionally present in about 3-8% individuals. Lies in the median plane. Separates 2 half of frontal bone and fuses at the 6 yrs of age.
  14. 14. Other features are: Vertex- highest point on saggital suture Bregma- meeting point between the coronal and sagittal sutures. Lambda- meeting point between sagittal and lambdiod sutures. Obelion- point on sagittal suture between two parietal foramina
  15. 15. PARIETAL BONES The main bone on the side of the skull. It articulates (joins) with the other parietal bone in the midline (top of the head), with the frontal bone in front of it, with the occipital bone behind it, and with the sphenoid and temporal bones lower down on the side of the skull.
  16. 16. Clinical anatomy Frontanelles are sites of growth of skull, permitting growth of brain and pulps to determine age. If frontanelles fuse early- brain growth stunted, and child will be less intelligent. Anterior frontenelle: bulging- increased intracranial pressure. depressed- decreased intracranial pressure
  17. 17. NORMA OCCIPITALIS Convex upward and on each side , flattened below. Bones seen: 1) posterior part of parietal bones, above. 2)Upper part of squamous part of the occipital bone below, 3)mastoid part of the temporal bone on each side.
  18. 18. Sutures seen are: 1)Lambdoid suture 2)Occipitomastoid suture 3)parietomastoid suture 4)Posterior part of saggital suture.
  19. 19. OCCIPITAL BONE From the Latin, meaning the part of the head opposite the front. It occupies the posterior and inferior part of the skull. The occipital bone articulates (joins) with the parietal and temporal bones of the skull, the sphenoid bone in front of it, and the first cervical vertebra (the atlas) beneath it
  20. 20. Landmarks: Foramen magnum: large hole, allowing passage of the spinal cord External occipital protuberance (EOP): prominent projection on back of occiput Nuchal lines: a superior and inferior line running laterally from the midline, serve as a point of muscle attachment
  21. 21. Foramen magnum Wider posterior a. Lowest part of medulla oblongata b. Three meninges Subarachanoid space a. Spinal accessory nerves b. Vertebral arteries c. Sympathetic plexus d. Post spinal arteries e. Ant spinal arteries Narrow anterior part a. Apical ligament of dens b. Vertical band of cruciate ligament c. Membrana tectoria
  22. 22. NORMA FRONTALIS Roughly oval in outline, being wider above than below. Bones seen are: 1)frontal bone. 2)right and left maxillae form the upper jaw. 3)right and left nasal bones. 4)zygomatic bones 5) mandible.
  23. 23. Sutures seen are 1)internasal 2)frontonasal 3)nasomaxillary 4)lacrimomaxillary 5)frontomaxillary 6)intermaxillary 7)zygomaticomaxillary 8)zygomaticofrontal
  24. 24. FRONTAL BONE The large bone that makes up the forehead and supplies the upper edge and roof of the orbit (eye socket). The frontal bone articulates (comes together) with a number of other bones including the parietal, nasal, ethmoid, maxillary, and zygomatic bones. Landmarks: Squama: flat portion that forms the forehead
  25. 25. Supraorbital margin: ridge under the eyebrow, forming the upper part of the orbit (eye socket) Supraorbital foramen: small hole within supraorbital margin for blood vessels and nerves Frontal sinuses: hollow spaces behind the squama, act as sound chambers to give the voice resonance.
  26. 26. Clinical anatomy Nasal bone is the most commonly fractured bone of the face. Mandible and parietal eminence are next bone to be fractured.
  27. 27. NORMA LATERALIS Bones seen are: 1)frontal 2)parietal 3)occipital 4)temporal 5)sphenoid 6)zygomatic 7)mandible 8)maxilla 9)nasal
  28. 28. A large irregular bone situated at the base and side of the skull. The temporal bone is connected with the mandible (the jaw bone) via the temporomandibular (TM) joint. The temporal bone is formed of three parts (squamous, tympanic and petrous) that are distinct at birth but then fuse. The petrous portion of the temporal bone contains the structures of the inner ear. TEMPORAL BONE
  29. 29. Landmarks: Squama: flat portion of the temporal bone forming the anterior and superior part of the temple Zygomatic process: process forming part of the cheek. Petrous portion: internal, forming part of the floor of the cranium. Contains the ear canal and internal ear structures. Mandibular fossa: socket between squama and petrous portion, articulates with the condyle of the mandible (TMJ)
  30. 30. External auditory meatus: opening to the ear canal Mastoid process: bony prominence behind the external auditory meatus Styloid process: looks like an elephants tusk located between the mastoid process and the jaw. Acts as a point of attachment for muscles and ligaments.
  31. 31. Clinical anatomy Pterion is the thin part of the skull. In roadside accidents, the anterior division of middle meningeal artery may be ruptured, leading to clot formation between the skull bone and durameter or extradural haemorrhage. The clot compresses the motor area of the brain leading to paralysis of the opposite site. The clot must be sucked out at the earliest by trephining. The head must be protected by a helmet.
  32. 32. NORMA BASALIS Divided arbitrarily into- o anterior o middle o and posterior parts.
  33. 33. A prominent, irregular, wedge-shaped bone at the base of the skull. The sphenoid bone has been called the "keystone" of the cranial floor since it is in contact with all of the other cranial bones. Sphenoid bone resemble a bat with outstretched wings. Comprises: a body in the centre two lesser wings from the anterior part two greater wings from the lateral part two pterygoid processes. SPHENOID BONE
  34. 34. Landmarks Greater wings: large lateral projections of bone that help to form the lateral border of the skull Lesser wings: smaller lateral projections of bone above the greater wings Pterygoid processes: two long downward projections from the greater wings that act as a point of muscle attachment. Sella turcica: known as the Turkish Saddle which cradles the pituitary gland.
  35. 35. ETHMOID BONE An irregularly shaped, bone that provides the floor of the front part of the skull and the roof of the nasal cavity. The ethmoid consists of two masses of thin plates enclosing air cells and looks like a sieve. Landmarks: Lateral masses: form most of the wall between the nasal cavity and the orbits Perpendicular plate: forms the superior portion of the nasal septum Cribiform plate: forms the roof of the nasal cavity
  36. 36. Olfactory foramina: small holes within the cribiform plate for passage of the first cranial nerve (for smell) Crista galli: upward extension of bone above the cribiform plate, acts as an anchoring point for one of the coverings of the brain. Nasal concha (turbinates): two scroll-shaped projections with a