The shear modulus of connections between tendon fascicles

Values of shear moduli in collagenous composites such as tendon are necessary to understand their mechanical properties fully. Simple shear tests were used to measure the initial shear modulus longitudinal and transverse to the fascicle direction in three tendons of the bovine hind limb: calcaneus, superfical digital flexor and deep digital flexor. The shear modulus was similar in both directions and in all three tendons, although the superficial digital flexor tendon may be marginally stiffer than the other two tendons. Tendon fascicles are laterally bounded by a loose sheath of crossed-ply fibres. Slippage between tendon fascicles may dominate the shear behaviour of the whole tissue. The absolute values of the shear moduli measured (2.94 - 6.38 kPa) are small, indicating that lateral force transmission between fascicles by shear is not efficient at small strains.