Related Experiment Video
Updated: Jul 10, 2026

Biomechanical Testing of Murine Tendons
Published on: October 15, 2019
Mechanical properties of intrasynovial and extrasynovial tendon fascicles
Richard H Shin1, Chunfeng Zhao, Mark E Zobitz
1Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Background:
Tendon grafting in tendon reconstruction often involves the interchange of intrasynovial and extrasynovial tendons. Although many studies have examined the cellular and biological differences between tendons of various sources, few have studied the mechanical properties of these two different types of tendons. The purpose of this study was to investigate the mechanical properties of intrasynovial and extrasynovial tendons.
Methods:
Canine peroneus longus (extrasynovial) and flexor digitorum profundus (intrasynovial) tendons, further subdivided into intrasynovial tendinous and intrasynovial fibrocartilaginous segments, were used in the study. An indentation test was used to measure the compressive modulus. Tensile testing was performed on 400mum longitudinal sections.
Findings:
The compressive modulus of the intrasynovial fibrocartilaginous segment was significantly higher than that of the intrasynovial tendinous segment, which was in turn significantly higher than that of the extrasynovial tendon (P<0.0001). The tensile modulus of extrasynovial tendon was significantly higher than that of intrasynovial fibrocartilaginous and intrasynovial tendinous segments (P<0.005). The tensile modulus of the intrasynovial fibrocartilaginous and tendinous segments was not significantly different (P=0.14).
Interpretation:
The results suggest that extrasynovial tendons exhibit superior tensile properties but inferior compressive properties when compared to intrasynovial tendons, which is consistent with their biological role in situ, but which could lead to complications when these tendons are repositioned during tendon graft surgery.
Related Concept Videos
Skeletal Muscle Anatomy
Layers of Connective Tissue Proper
Overview of Muscle Tissues
Elasticity
Elasticity is the ability of muscles to stretch and return to their original shape. This property is partly due to elastic fibers — macromolecules that run through the muscles. These fibers are firm and resilient,...
Fascicle Arrangement in Skeletal Muscles
The four primary types of muscle based on fascicle arrangement are:
Structural Joints: Synovial Joints
Gross Anatomy of Skeletal Muscles

