#myofibril__myofibrilla  one of many contractile filaments that make up a striated muscle fiber
  supertype:  fibril__filament__strand  a very slender natural or synthetic fiber
  part of:  striated_muscle_cell
  part:  sarcoplasm  the cytoplasm of a striated muscle fiber
  part:  sarcomere  one of the segments into which a myofibril is divided

No statement uses or specializes myofibril; click here to add one.