A blade segment (4, 8) for a refiner (1) for refining fibrous material has first (20) and second (21) end edges opposite one another in a direction of a longitudinal axis (LA) of the blade segment (4, 4a, 4b, 8, 8a, 8b), and first (22) and second (23) side edges which extend between the first end edge and the second end edge. The blade segment has a refining surface (5, 9) with blade bars (26) and grooves (27) therebetween on a front surface (25) of the blade segment (4, 8). At least one side edge (22, 23) has at least two edge portions (31, 33, 35, 41, 43, 45) arranged to deviate from the direction of the longitudinal axis (LA) of the blade segment (4, 4a, 4b, 8; 8a, 8b) and connected by an elbow (32, 34, 42, 44) between each two edge portions (31, 33, 35, 41, 43, 45).

A blade segment (4, 8) for a refiner (1) for refining fibrous material has first (20) and second (21) end edges opposite one another in a direction of a longitudinal axis (LA) of the blade segment (4, 4a, 4b, 8, 8a, 8b), and first (22) and second (23) side edges which extend between the first end edge and the second end edge. The blade segment has a refining surface (5, 9) with blade bars (26) and grooves (27) therebetween on a front surface (25) of the blade segment (4, 8). At least one side edge (22, 23) has at least two edge portions (31, 33, 35, 41, 43, 45) arranged to deviate from the direction of the longitudinal axis (LA) of the blade segment (4, 4a, 4b, 8; 8a, 8b) and connected by an elbow (32, 34, 42, 44) between each two edge portions (31, 33, 35, 41, 43, 45).