Title
Die Biomechanik des Kieferapparates beim Stierkopfhai: Heterodontus portusjacksoni = Heterodontus philippi (Advances in Anatomy,,Used
Delivery time: 8-12 business days (International)
Vor rund 350 Millionen Jahren drfte die Klasse der Chondrichthyes entstanden sein, deren bekannteste Vertreter die modernen Haie sind. Die Untersuchung ihrer Morpho logie erscheint interessant, weil sie einen Konstruktionszustand reprsentieren, der die Grundlage fr das Verstndnis von Phylogenie und Ontogenie vieler Wirbeltiere bildet. Bei der Erforschung des funktionellen Baues des cranialen Skelettes haben deshalb schon um die Jahrhundertwende Tiesing (1896), Sewertzoff (1899) und Luther (1908/ 1909) auf die Ordnung der Selachier zurckgegriffen. Leider gingen diese ersten An stze wie auch die Arbeiten von Garman (1913), Daniel (1915) und Graf Haller (1926) ber Beschreibungen und Vergleiche kaum hinaus. Beim Menschen unternahmen zu nchst Weigele (1921) und Richter (1921), spter auch Molitor (1969) und Kppers (1971) den Versuch, mechanische Gesetzmigkeiten im Bau des Unterkiefers aufzu finden. Doch erst 1963 gelang es Crompton und Parkyn, die von sugetierhnlichen Reptilien ausgingen, allgemeine Regeln der Statik auf die Unterkieferentwicklung bei den Sugetieren zu bertragen. Sie kamen zu dem Schlu, da in der Entwicklungs reihe zu den Sugetieren zwei Tendenzen eine wichtige Rolle spielen: die fortschrei tende Gelenkentlastung und die effektivere Ausnutzung der Muskelkraft durch Anlage eines lngeren Hebelarmes. Alexander (1968) beschftigte sich allgemein mit Tierme chanik und widmete dem Gebiet der Unterkieferstatik bei Sugetieren einige Kapitel, wobei er hauptschlich auf Crompton (1963) zurckgriff. Alle diese Untersuchungen beschftigen sich rein theoretisch hauptschlich mit der Kaumuskulatur, deren Zug richtung, deren Hebelarmen und der sich daraus ergebenden mechanischen Beanspru chung des Kiefers.
By changing our most important processes and
products, we have already made a big leap forward. This ranges from the
increased use of more sustainable fibers to the use of more
environmentally friendly printing processes to the development of
efficient waste management in our value chain.
⚠️ WARNING (California Proposition 65):
This product may contain chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.
For more information, please visit www.P65Warnings.ca.gov.
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Shipping & Returns
Shipping
We ship your order within 2–3 business days for USA deliveries and 5–8 business days for international shipments. Once your package has been dispatched from our warehouse, you'll receive an email confirmation with a tracking number, allowing you to track the status of your delivery.
Returns
To facilitate a smooth return process, a Return Authorization (RA) Number is required for all returns. Returns without a valid RA number will be declined and may incur additional fees. You can request an RA number within 15 days of the original delivery date. For more details, please refer to our Return & Refund Policy page.
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We provide a 2-year limited warranty, from the date of purchase for all our products.
If you believe you have received a defective product, or are experiencing any problems with your product, please contact us.
This warranty strictly does not cover damages that arose from negligence, misuse, wear and tear, or not in accordance with product instructions (dropping the product, etc.).
Warranty
We provide a 2-year limited warranty, from the date of purchase for all our products.
If you believe you have received a defective product, or are experiencing any problems with your product, please contact us.
This warranty strictly does not cover damages that arose from negligence, misuse, wear and tear, or not in accordance with product instructions (dropping the product, etc.).
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Secure Payment
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
We accept payments with :
Visa, MasterCard, American Express, Paypal, Shopify Payments, Shop Pay and more.