A low-cost system to acquire 3D surface data from anatomical samples

The technology of optical 3D imaging sensors or 3D scanners (laser and structured light sensors) has become widely available over the last few years. A wider diffusion of this technique in anatomical laboratories could lead to a revolution in the field of anatomy: cadaver dissections could be easily documented in 3D, and specimens stored in museums could be easily scanned and the 3D models shared. In the present article, a simple, versatile, economical and widespread 3D scanner, the Kinect sensor, is validated to show its potential use for 3D scanning of anatomical specimens. The comparison of 3D models of anatomical specimens (a collection of skulls) with the respective 2D photographs showed that 3D models were superior to the photographs, the latter being affected by some distortions due to perspective. Moreover, the 3D models allowed for measuring angles, distances, circumferences between every part of the model, or measuring volumes and surfaces, which, of course, were not available using the 2D images. Due to the low cost of this system, its simplicity of use and its widespread availability, it is desirable that in the future, anatomical specimens from museums will become more available as 3D objects. These could greatly simplify the quantitative analysis of rare specimens, such as fetal monstrosities or anatomical variations

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Testing the model of optic chiasm formation in human beings.

Recent data from animal studies allow us to understand how the optic commissure formed. However, their validity in humans has not yet been demonstrated. Clues from human teratological cases provide useful information to test the validity of animal models and suggest other morphogenetic mechanisms. Janiceps are non-viable, rare cases of co-joined embryos fused along the frontal plane, with two composite faces, half formed by each of the embryos. Their development after fusion is of interest to study the optic chiasm. The analysis of the optic nerves and of the skull by magnetic resonance imaging or direct inspection of three different cases of Janiceps showed a shared hypophyseal fossa that laterally could contain a compound optic commissure between the eyes of the same composite face (heterologues), but not between the eyes from the same individual (homologue). The current model of the optic commissure formation correctly predicts these findings in humans because the optic commissure are driven toward the midline by local factors and not by target regions. However, our data suggest that the overall geometry of the region is important for a successful decussation of the axons, and additional mechanisms are involved in midline differentiation.