Meeting Abstract
Jaw muscles are important components of the vertebrate skull in that they drive feeding behavior by loading and moving the jaws. Jaw muscles present a variety of morphologies and functions that lend insight into behavior and evolution. However, it remains challenging to describe the 3D architecture of jaw muscles using classical 2D dissection-based methods or costly MRI-based methods. Therefore new methods in visualizing and measuring 3D muscle architecture are welcome. This study uses diffusible iodine contrast-enhanced CT (diceCT) to visualize muscle morphology and reconstruct the 3D architecture of jaw muscles using fiber-tracking software in order to determine functional differences in reptile jaw muscles. We sampled a simple muscle, m. intermandibularis, a more complex muscle m. pterygoideus and other neighboring jaw muscles in Tokay gecko (Gekko gecko) in order to test computational approaches. We immersed a gecko head in Lugol’s Iodine solution in order to increase the contrast of muscles for microCT. We segmented the muscles and imported the models into Image3d.exe software. 3D orientations of individual fibers were visualized in MATLAB and further analyzed in R. We found the mpterygoideus muscle possesses a diversity of differently-oriented muscle fibers whereas m. intermandibularis was simpler suggesting these approaches work. This is the first 3D visualization of jaw muscle fibers in the heads of reptiles and one of the first to incorporate computational techniques with our new diceCT imaging protocols. This work will enable us to better understand the diversity, function and biomechanical significance of jaw muscles in the skulls of animals.
