ABSTRACT
Skeletal muscle is known to be set at an over-stretched length in clinical tendon transfer. Such chronic stretching of skeletal muscle increases the serial sarcomere number required for muscle adaptation. Passive tension of the muscle must be affected during the adaptation. Thus, the objective of this study was to clarify the origin of increased passive tension after stretched tendon transfer in an animal model. The distal tendon of the extensor digitorum of the second toe was transposed to the extensor retinaculum at 3.7 mm of muscle sarcomere length. The contralateral muscle served as control. Muscle passive length-tension curves were measured at 1 week and 4 weeks after the transfer to the bilateral muscles. After functional measurements were taken, the muscles were dissected into fiber bundles and single muscle fibers to measure their passive mechanical properties with a micro force transducer. Passive tension was increased in the transferred muscle with a steeper inclination and leftward shift of muscle length-tension curve. Elastic modulus of the transferred fiber bundle increased at both time points, while those of the transferred single fibers increased only at 1 week. Results of the study suggest that the transferred muscle increased passive tension mainly due to proliferation of extracellular connective tissue within the muscle. Increased passive tension was a characteristic feature for the transferred muscle, which may ultimately represent a target for therapeutic intervention to optimize muscle function.
ABSTRACT
Objective To explore the evidence for the morphologic comparability between the meridians and interstitial connective tissues in the lower limb with auto-marked and 3D-Rebuilding technology. Methods First,the muscles were extracted and noise was eliminated;With edge detection a convex hull of the muscles edge was found;The interstitial connective tissue points were marked in the cross section images of left leg from the digital dataset of Virtual Chinese Human-Male1(VCH-M1).Finally,the auto-marked images were reconstructed with 3D-Doctor. Results The reconstructed meridians in the lower limb auto-marked with computer procedures tallied basically with the meridians and collaterals recorded in Traditional Chinese Medicine(TCM) illustrative graphics.Conclusion Having the advantages of digital anatomic study on acupuncture points earlier and mature 3D-Rebuilding techniques,the department of Anatomy of South Medical University cooperated with the Department of Scientific Calculation and Computer Application of Sun Yat-sen University to devise a set of computer programs which could be used to AutoMark interstitial connective tissues in Virtual Human lower limbs and then reconstruct virtual fascia meridians which corresponded with the TCM records.This method avoided man-made error to a certain degree in the process of recognizing and rebuilding of fascias.The study is significant to explore the morphologic comparability between the meridians and collaterals and interstitial connective tissues in human lower limb.