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Axial Skeleton PowerPoint Presentation
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Axial Skeleton

Axial Skeleton

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Axial Skeleton

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    1. Axial Skeleton Skull Cephalization Neurocranium Protects brain & sensory structures Phylogeny common to all vertebrates Replacement bone

    2. Chondrocranium development Prechordal cartilage (trabeculae cranii) form Underneath brain Anterior to notochord

    4. Prechordal cartilage Form under forebrain region Form nasal = olfactory capsules Form optic capsules in orbit Form rostrum Finally expands to become ethmoid plate

    8. Parachordal cartilage Forms beside and posterior to notochord Forms floor of hindbrain Expands to form basal plate Forms occipital condyles (1-2) and foramen magnum

    11. Sensory capsules As floor of cranium forms, so do sensory capsules Olfactory capsule Otic capsule for inner ear structures Optic capsule (not attached outer covering of eyeball)

    14. Plate expansion Ethmoid plate expands and unites with olfactory capsule Basal plate expands and unites with otic capsule Formina remain for nerves & blood vessels Hypophyseal fenestra remains for pituitary gland

    15. Question Singular of foramina? Fenestra?

    16. Ossification Centers Ethmoid plate, basal plate & sensory capsules ossify Four ossification centers Occipital (back), Otic (ear), Sphenoid (floor), Ethmoid (floor)

    18. Occipital Ossification Center Foramen magnum Basioccipital Exoccipital Supraoccipital Occipital Condyles

    22. Otic ossification center

    23. Sphenoid ossification center Basisphenoid Presphenoid/Sphenethmoid

    26. Ethmoid ossification center Ethmoid plate Olfactory capsules Turbinates in mammals

    31. Neurocranium Look at Skull & Lower Jaw Components page

    32. Key Points What is one important trend of the NEUROCRANIUM from the Skull & Lower Jaw Components page?