Elizabeth L. Brainerd
Ph.D., Harvard University

These are exciting times in the field of vertebrate morphology. Imaging technologies such as high-resolution CT scanning, MRI, and laser scanning confocal microscopy are opening up vast worlds of cross- sectional and three-dimensional anatomy. In functional morphology and biomechanics, new tools for micrometry, force measurement, 3D flow visualization, 3D motion capture, and mathematical modeling are providing ever more sophisticated understandings of the interactions between morphology and environment. Studies of vertebrate functional morphology, biomechanics, paleontology, and development are poised at the edge of a revolution in our ability to capture and quantify complex morphology and function in 4D (3 spatial dimensions plus time), and to integrate our understandings of function, development, and evolution. With my colleagues in the vertebrate morphology group at Brown, we are currently developing a 3D x-ray technology for visualizing rapid skeletal movement. This new technology, "X-ray Reconstruction of Moving Morphology (XROMM)", combines static 3D data from CT scans with skeletal movement data from high-speed x-ray videos. XROMM produces highly accurate 3D animations of skeletal elements moving in space. XROMM makes it possible to study many aspects of skeletal kinematics, such as long axis rotation of bones, putative bending of fine bones in small animals, and the relative 3D motions of the articular surfaces of joints that are inaccessible with other techniques. In addition, XROMM provides more accurate data for input into musculoskeletal models, such as joint angles for inverse dynamics and neural control models. We are currently using XROMM to study jaw movement and temporomandibular joint function in pigs, joint and muscle kinematics in jumping frogs, feeding in ducks, and rib and intercostal muscle function in lizards.