NOVELTY - The wind turbine blade comprises activation mechanisms for controlling a position and/or movement of an aerodynamic device (101). The device is movably connected to a blade body (107), where the device is partly divided into a number of sections (300) by interstices or connecting portions having higher elasticity than the elasticity of the sections. The interstices or connecting portions are extended partly through a thickness of the device from a trailing edge (307) of the device in chordwise direction (308) such that the overall longitudinal bending flexibility of the device is increased.    USE - Wind turbine blade.    ADVANTAGE - The aerodynamic device is partly divided into a number of sections by interstices or connecting portions comprising a higher elasticity, thus increasing the overall longitudinal bending flexibility of the device, and hence lowering force and power consumption, increasing the operability of the aerodynamic device and reducing the wear of movable parts of the blade. The wind turbine blade is designed, so as to allow a wider range and efficient manufacturing methods, and easy maintenance. The neighboring device sections are partly overlapped in the relaxed state of the blade, thus increasing the flexibility of the aerodynamic device in a simple manner without the use of additional materials. The interstices are arranged at even intervals along the longitudinal direction of the device, thus increasing the bending and twisting of the aerodynamic device along the entire length, and hence reducing frictional force in joints and connection parts of the activation mechanisms. The activation mechanisms allow faster activation of the aerodynamic device. The blade utilizes a pressure hose system that is of low weight and low manufacturing cost. The blade utilizes filling material that seals fully or partially the interior parts of the aerodynamic device or the blade body, thus preventing dust particles or fluid from entering the blade.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a wind turbine blade that is subjected to lengthwise bending deformation due to wind pressure, where the blade comprises a movable trailing edge with a number of device segments.    Aerodynamic device (101)    Blade body (107)    Number of sections (300)    Trailing edge (307)    Chordwise direction (308)