lecture 5 - jaws and teeth

Department of Geological Sciences | Indiana University (c) 2013, P. David Polly

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Canis familiaris. P.D. Polly

Reading: Benton, Chapter 10

Comparative structure

Jaws and Teeth


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Barghusen and Hopson, 1979, The Endoskeleton

Branchial basket of lamprey (agnathan)


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Shark jaws (Chondricthyes)


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Teleost protrusible jaws


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Comparative jaw muscles in mammal and reptile


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Jaw suspension in vertebrates

Amphistylic (ancestral condition)

Hyostylic (condrichthyes)

Autostylic (Sarcopterygians and tetrapods)


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Dog skull (P. David Polly)

Structures associated with jaw movements in mammals

Joint: condyle of the mandible fits into the glenoid fossa of the squamosal (note same name as glenoid fossa of the pectoral girdle)

Zygomatic Arch: composed of the jugal (or zygomatic) and squamosal bones, muscle attachment along lower margin

Temporal Fossa: area for muscle attachment and movement of the mandible, site of muscle attachment

Coronoid process of the mandible: site of muscle attachment

Masseteric fossa of the mandible: site of muscle attachment

Angular process of the mandible: site of muscle attachment


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(Evans, Miller’s Anatomy of the Dog)

Muscles that move the mandibleTemporalis - originates on the side of the braincase, inserts on the coronoid process, pulls the mandible upward and backward.

Masseter - originates on the zygomatic arch, inserts in the masseteric fossa and on the lateral angle of the mandible, pulls the mandible upward, laterally, and forward.

Pterygoideus - originates on the pterygoid plates, inserts on the medial angle of the mandible, pulls the mandible upward, medially, and forward.

Temporalis

Masseter

Pterygoideus


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Dog skull (P. David Polly)

Muscle action to elevate (close) the mammalian mandible

Massete

r

Temporalis


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temporalis

masseter pterygoideus

Dorsal and medio-lateral action of the muscles


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Model by Alistair Evans, Monash Universityhttp://users.monash.edu.au/~arevans/3d.html

Animated model of teeth in actionNote how tall trigonid of lower molars passes between upper teeth and how the protocone of the upper molars slides across low talonid basin of lowers in mortar-and-pestle fashion

http://users.monash.edu.au/~arevans/3d.html

http://users.monash.edu.au/~arevans/3d.html


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Mesial

Distal

Lingual (or Palatal)

Labial (or Buccal)

Anatomical directions for the dentition


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Homo sapiens. P. D. Polly

Human jaws and dentition

Alveolar bone

Coronoid process

Condylar process

Angular process


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Tooth eruption in humans


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Tooth development schematic view


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Tooth structure, development, and attachment

Pleurodont Acrodont Thecodont


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The Fossil Forum

Scales and teeth - developmentally homologous structures

Gar scales

•Composed of bone, dentine, and enamel (or variants)•Develop from interaction between

surface ectoderm layer and deeper mesoderm layer•Mouth of deuterostomes is formed by

invagination of ectoderm to connect with gut tube

Shark teeth


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Splanchnocranium in humans


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A.D.A.M. Atlas of Anatomy

Innervation of the teeth and mandible

Root of trigeminal nerve (V)

Mandibular division of trigeminal

(V3)

Maxillary division of trigeminal (V3)

lecture 5 - jaws and teeth

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