Abstract: An interspinous implant includes an implant body extending along a longitudinal axis and having, in succession: a rear part having a rear end, and a central part shaped to extend between two spinous processes of two adjacent vertebrae, the central part extending the rear part. The implant further includes a front part extending the central part, in the opposite direction from the rear part, and tapering down to a front end of streamlined shape. The implant body has an anterior face intended to face toward the vertebrae and in which there is formed an anterior groove of curvilinear shape, extending from the rear end as far as the front end in a curvilinear direction, to accept at least a portion of an implantation prong of an implantation ancillary.