A bone attachment collar, comprising: a collar wall defining a cavity and having at least one wall aperture; a distal portion comprising an opening and a collar seat projecting inward and supporting a head of a bone fastener; characterised in that a proximal portion having a hinged lid comprising a lid aperture and a lid hook opposite the hinge wherein the lid hook is adapted to engage a hook engagement member in the collar wall; and a spinal rod locking device projecting through the central lid aperture of the hinged lid, which comprises: a nut which is adapted to rotate a partial turn about an axis from an unlocked position to a locked position and which possesses a distal cam surface and a collar engagement member projecting radially from a segment of an outer diameter of the nut, wherein the distal cam surface is adapted to impart distal force to a clamp member and the collar engagement member is adapted to rotatably engage a collar overhang of the collar wall in the locked position and not engage the collar wall in the unlocked position; and the clamp member possessing a proximal cam surface, which interacts with the distal cam surface of the nut, and which is adapted to receive distal force from the nut and impart distal force to a rod extending through the wall aperture; wherein at least a portion of the spinal locking device is within the cavity defined by the collar wall. a collar wall defining a cavity and having at least one wall aperture; a distal portion comprising an opening and a collar seat projecting inward and supporting a head of a bone fastener; characterised in that a proximal portion having a hinged lid comprising a lid aperture and a lid hook opposite the hinge wherein the lid hook is adapted to engage a hook engagement member in the collar wall; and a spinal rod locking device projecting through the central lid aperture of the hinged lid, which comprises: a nut which is adapted to rotate a partial turn about an axis from an unlocked position to a locked position and which possesses a distal cam surface and a collar engagement member projecting radially from a segment of an outer diameter of the nut, wherein the distal cam surface is adapted to impart distal force to a clamp member and the collar engagement member is adapted to rotatably engage a collar overhang of the collar wall in the locked position and not engage the collar wall in the unlocked position; and the clamp member possessing a proximal cam surface, which interacts with the distal cam surface of the nut, and which is adapted to receive distal force from the nut and impart distal force to a rod extending through the wall aperture; a nut which is adapted to rotate a partial turn about an axis from an unlocked position to a locked position and which possesses a distal cam surface and a collar engagement member projecting radially from a segment of an outer diameter of the nut, wherein the distal cam surface is adapted to impart distal force to a clamp member and the collar engagement member is adapted to rotatably engage a collar overhang of the collar wall in the locked position and not engage the collar wall in the unlocked position; and the clamp member possessing a proximal cam surface, which interacts with the distal cam surface of the nut, and which is adapted to receive distal force from the nut and impart distal force to a rod extending through the wall aperture; wherein at least a portion of the spinal locking device is within the cavity defined by the collar wall.