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Axial Skeleton - Skull Neurocranium Dermatocranium Splanchnocranium.

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Presentation on theme: "Axial Skeleton - Skull Neurocranium Dermatocranium Splanchnocranium."— Presentation transcript:

1 Axial Skeleton - Skull Neurocranium Dermatocranium Splanchnocranium

2 Dermatocranium Phylogeny – membrane bone which evolved from dermal armor Roofing bones Along side and above brain

3 Roofing Bones Nasal Frontal Parietal Orbital – Lacrimal – Jugal = Infraorbital = Zygomatic Squamosal




7 Look at the Skull & Lower Jaw components page. Examine the roofing bones.

8 Upper jaw Premaxilla Maxilla



11 Lower Jaw Dentary - largest Splenial – small, dorsomedial Surangular - lateral Angular – medial, becomes typanic bulla Coronoid – medial Prearticular – medial & caudal – becomes anterior malleus in mammals




15 Key Points Look at upper and lower jaw dermatocranium bones on Skull & Lower Jaw Components page Give an example of homology. What trend do you see in lower jaw evolution?

16 Primary Palate Bones Roof of oropharyngeal cavity in fish, amphibians Roof of nasal cavity in amniotes


18 Primary Palate Vomer Palatine Pterygoid



21 Primary Palate Examine Skull & Lower Jaw Components page

22 Dermatocranium Operculum

23 Key Point Describe dermatocranium bones in the shark…

24 Axial Skeleton - Skull Neurocranium Dermatocranium Splanchnocranium – Visceral skeleton

25 Splanchnocranium Supports & allows movement of jaws, gill, tongue Associated with hearing Ancient in evolution Replacement bone

26 Splanchnocranium Typically 6 gill slits between Visceral arches A typical visceral arch that is gill in function has five segments – Pharyngobranchial – Epibranchial – Ceratobranchial – Hypobranchial – Basibranchial



29 Splanchnocranium Mandibular arch = Visceral Arch I Palatoquadrate Mandibular = Meckel’s Cartilage



32 Splanchnocranium Hyoid arch = Visceral arch II Hyomandibula Ceratohyal Basihyal


34 Interrelationships The neurocranium, dermatocranium and splanchnocranium eventually becomes intimately associated to form one single, firm skull

35 Key Point Describe the origin of jaws from this picture

36 Key Point The three main components of the cranium are:

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