Spinal fixation system capable of being mounted on a vertebra of the spine for attachment to a rod (10), said vertebra a rear wall near which said rod and side walls of which extends projecting ribs and / or transverse processes, said system comprising a piece (12) capable of binding arranged in front of said rib and / or said transverse process, and bondable to said rod (10) characterized in that the system also comprises: - a flexible strap (42) of elongate shape capable of bonding together said connecting piece and at least one rib and / or a transverse process and, - means (36) integral adjustable locking said junction piece, said tie (42) a first end (44) integral with said part (12) connecting and a second end (46) free slidable in said junction piece forming a loop, said means locking susceptible to keep fixed position simultaneously said junction piece with respect to said rod and a portion of said strap between said ends, this being susceptible portion locked in translation relative to said connecting piece by said locking means adjustable, so the loop has a certain length so that the relative displacement of said rod (10) and said vertebra senses crashes or positions with each other.Sistema de fijación vertebral susceptible de montarse en una vértebra de la columna vertebral para unirla a una varilla (10), presentando dicha vértebra una pared posterior cerca de la cual se extiende dicha varilla y paredes laterales de las cuales sobresalen las costillas y/o las apófisis transversas, comprendiendo dicho sistema una pieza (12) de unión susceptible de disponerse enfrente de dicha costilla y/o de dicha apófisis transversa, y susceptible de unirse a dicha varilla (10) caracterizado porque el sistema también comprende: - una ligadura (42) flexible de forma alargada susceptible de unir entre sí dicha pieza de unión y al menos una costilla y/o una apófisis transversay, - medios (36) de bloqueo regulables solidarios con dicha pieza de unión, presentando dicha ligadu
