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Knockout mice lacking myostatin (Mstn), a negative regulator of the growth of skeletal muscle, develop significant increases in the relative mass of masticatory muscles as well as the ability to generate higher maximal muscle forces. Wild-type and Mstn-deficient mice were compared to investigate the postnatal influence of elevated masticatory loads due to increased jaw-adductor and bite forces on the biomineralization of mandibular articular and cortical bone, the internal structure of the jaw joints, and the composition of temporomandibular joint (TMJ) articular cartilage. To provide an interspecific perspective on the long-term responses of mammalian jaw joints to altered loading conditions, the findings on mice were compared to similar data for growing rabbits subjected to long-term dietary manipulation. Statistically significant differences in joint proportions and bone mineral density between normal and Mstn-deficient mice, which are similar to those observed between rabbit loading cohorts, underscore the need for a comprehensive analysis of masticatory tissue plasticity vis-à-vis altered mechanical loads, one in which variation in external and internal structure are considered. Differences in the expression of proteoglycans and type-II collagen in TMJ articular cartilage between the mouse and rabbit comparisons suggest that the duration and magnitude of the loading stimulus will significantly affect patterns of adaptive and degradative responses. These data on mammals subjected to long-term loading conditions offer novel insights regarding variation in ontogeny, life history, and the ecomorphology of the feeding apparatus.

There are surprisingly few experimental models of neural growth and cranial integration. This, and the dearth of information regarding fetal brain development, detracts from a mechanistic understanding of cranial integration and its relevance to the ontogenetic and interspecific patterning of the form of the skull. To address this shortcoming, our research uses transgenic mice expressing a stabilized form of β-catenin to isolate the effects of encephalization on the development of the basi- and neuro-cranium. These mice develop highly enlarged brains due to an increase in neural precursor cells, and differences between transgenic and wild-type mice are predicted to result solely from variation in relative brain size. By focusing on prenatal growth, this project adds to our understanding of a critically important period when major structural and functional interrelationships are established in the skull. Comparisons of wild-type and transgenic mice were performed using microcomputed tomography (microCT) and magnetic resonance imaging (MRI). These analyses show that the larger brains of the transgenic mice are associated with a larger neurocranium and an altered basicranial morphology. However, body size and postcranial ossification do not seem to be affected by the transgene. Comparisons of the rate of postcranial and cranial ossification also point to an unexpected effect of neural growth on skull development: increased fetal encephalization may result in a compensatory decrease in the level of cranial ossification. Therefore, if other life-history factors are held constant, the ontogeny of a metabolically costly structure, such as a brain, may occur at the expense of other cranial structures. These analyses indicate the benefits of a multifactorial approach to cranial integration using a mouse model.

Objective At the New York University College of Dentistry, we are faced with the challenge of teaching Head and Neck Anatomy to a class of approximately 380 first‐year students. We have developed an innovative anatomy curriculum that has proven effective in facilitating students’ learning and long‐term retention of the material. It has the added benefit of being time‐ and cost‐efficient. Here, we share the structure of our curriculum and examine the student outcomes and student feedback. Materials and Methods In this paper, we describe the evidence‐based methods used in our course and present measures of student success. We also surveyed students about aspects of the anatomy curriculum. Results Our curriculum efficiently manages cost, instructional time, and classroom space, while promoting student success. Over the last 9 years, NYU Dentistry students have achieved a mean first‐time pass rate of 98.6% and an average anatomy score of 1.74 standard deviations above the national mean on the National Board Dental Examination Part I. Students agree with instructor assessments of which features of the curriculum are valuable and state that the course helps them prepare for clinical courses. Conclusion We believe that the main factors in the success of our course are the small group setting, the benefits of spaced repetition and frequent quizzes, and the use of plastinated specimens in place of wet cadavers.

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