Dynamic Musculoskeletal Functional Morphology: Integrating diceCT and XROMM

Abstract

The tradeoff between force and velocity in skeletal muscle is a fundamental constraint on vertebrate musculoskeletal design (form:function relationships). Understanding how and why different lineages address this biomechanical problem is an important goal of vertebrate musculoskeletal functional morphology. Our ability to answer questions about the different solutions to this tradeoff has been significantly improved by recent advances in techniques for quantifying musculoskeletal morphology and movement. Herein, we have three objectives: (1) review the morphological and physiological parameters that affect muscle function and how these parameters interact; (2) discuss the necessity of integrating morphological and physiological lines of evidence to understand muscle function and the new, high resolution imaging technologies that do so; and (3) present a method that integrates high spatiotemporal resolution motion capture (XROMM, including its corollary fluoromicrometry), high resolution soft tissue imaging (diceCT), and electromyography to study musculoskeletal dynamics in vivo. The method is demonstrated using a case study of in vivo primate hyolingual biomechanics during chewing and swallowing. A sensitivity analysis demonstrates that small deviations in reconstructed hyoid muscle attachment site location introduce an average error of 13.2% to in vivo muscle kinematics. The observed hyoid and muscle kinematics suggest that hyoid elevation is produced by multiple muscles and that fascicle rotation and tendon strain decouple fascicle strain from hyoid movement and whole muscle length. Lastly, we highlight current limitations of these techniques, some of which will likely soon be overcome through methodological improvements, and some of which are inherent. Anat Rec, 301:378-406, 2018. © 2018 Wiley Periodicals, Inc.

Methods for characterization and optimisation of measuring performance of stereoscopic x-ray systems with image intensifiers

“…Videos from biplanar x-ray systems are becoming increasingly popular to analyse three-dimensional (3D) motion, especially within the field of biomechanics (Brainerd et al 2010, Camp et al 2016, Orsbon et al 2018. Since the analogue x-ray image intensifiers of such biplanar x-ray video systems typically show a persistence of luminescence after x-ray stimulation of only about 1 ms (Wang and Blackburn 2000), digital high-speed cameras are generally used to record the image intensifier's output screen at high frame rate (Snelderwaard et al 2002).…”

Integrating XMALab and DeepLabCut for high-throughput XROMM

“…Note that despite differing mean reprojection errors (see main text), mean rigid body error and resultant rotation values for the pig and monkey were comparable to that of the same trial tracked in XMALab. Joint coordinate systems were oriented following Menegaz et al (2015) and Orsbon et al (2018). The rx (x-axis rotation) trace was omitted because it failed to exceed the established noise threshold in both tracking methods.…”

“…(E-F) The resulting DeepLabCut + XMALab marker trajectory (magenta line) is accurate, and 8-13x faster to generate. The trajectories are the X and Y values taken from the marker’s XYZ coordinates that have been exported from XMALab, and transformed into an anatomical coordinate system with its origin at the posterior nasal spine (Orsbon et al (2018). Unfiltered (A & E) and filtered with a 30 Hz low-pass butterworth filter (B & F) trajectories are shown.…”

A digital dissection of two teleost fishes: comparative functional anatomy of the cranial musculoskeletal system in pike (Esox lucius) and eel (Anguilla anguilla)

“…Although several studies have presented 3D reconstructions of teleost anatomy both graphically (Anker, 1974;Adriaens & Verraes, 1996a,b) and digitally (Leysen et al 2011;Bouilliart et al 2015), these are almost all based on destructively sampled histological data; the non-destructive nature of contrast-enhanced CT makes it an attractive option, and the digital anatomical models can be readily used in biomechanical modelling applications Orsbon et al 2018).…”