Adjustable bone anchor assembly

An orthopedic medical apparatus comprising:

• a receiver member having a longitudinal aperture, a channel for receiving an elongated member transverse to said aperture, a lower opening, and a groove communicating with said longitudinal aperture, wherein a lower portion of said longitudinal aperture includes a pair of opposed substantially flat walls;
• a bone anchor member having a longitudinal axis and a head, said head having a substantially part-spherical portion and a pair of opposite flat portions, said flat portions being substantially parallel to said axis, at least a portion of said head being in said aperture;
• a crown member having a rounded lower surface, a pair of opposite substantially flat external surfaces, and a pair of opposite substantially cylindrical external surfaces, said crown member being placed in said aperture so that said lower surface is adjacent said head of said anchor member, wherein said pair of opposed substantially flat external surfaces are received in said longitudinal aperture adjacent said pair of opposed substantially flat walls of said receiver member;
• wherein said crown member includes a first opening extending laterally through one of said opposite flat external surfaces and a second opening extending laterally through the other of said opposite flat external surfaces, and wherein said pair of opposite flat portions of said bone anchor member are positioned at said first and second openings in said crown member and adjacent said pair of opposed substantially flat walls of said receiver member;
• and
• a retaining member at least partially within said groove and around at least a portion of said anchor member;
• and
• wherein said flat portions are arranged substantially parallel to said substantially flat external surfaces of said crown member and are also arranged substantially parallel to said pair of opposed substantially flat walls defined by said lower portion of said longitudinal aperture.

An orthopedic medical apparatus, comprising:

• a receiver member having an internal chamber with at least one substantially flat wall;
• a crown member at least partially in said chamber, said crown member having a rounded lower surface, a substantially flat external side surface, and an opening extending laterally through said substantially flat external side surface;
• and
• a bone anchor member having a longitudinal axis and head portion with at least one substantially flat wall portion, said head portion being adjacent said rounded lower surface of said crown member, said substantially flat wall portion of said anchor member being substantially parallel to said longitudinal axis and positioned at said opening in said crown member and adjacent said substantially flat wall of said receiver member, wherein said anchor member is limited to pivotal movement with respect to said receiver member in a single plane;
• and
• wherein said chamber has two substantially flat walls that are substantially parallel to each other, said crown member having a pair of said substantially flat external side surfaces with one of said openings extending laterally through each of said substantially flat external side surfaces, wherein said opposite substantially flat external side surfaces of said crown member are positioned adjacent and substantially parallel with said substantially flat walls defined by said chamber of said receiver member, and wherein said head portion has two substantially flat walls that are substantially parallel to each other and which are positioned at said openings in said crown member and adjacent said substantially flat walls of said receiver member.

An orthopedic medical apparatus comprising:

• a receiver member having a longitudinal aperture, a channel for receiving an elongated member transverse to said aperture, a lower opening, and a groove communicating with said longitudinal aperture, wherein a lower portion of said longitudinal aperture includes a pair of opposed substantially flat walls;
• a bone anchor member having a longitudinal axis and a head, said head having a substantially part-spherical portion and at least one flat portion, said flat portion being substantially parallel to said axis, at least a portion of said head being in said aperture;
• a crown member having a rounded lower surface, a pair of opposite substantially flat external surfaces, and a pair of opposite substantially cylindrical external surfaces extending from one of said flat external surfaces to an opposite one of said flat external surfaces to provide said crown member with an oblong disc configuration, said crown member being placed in said aperture so that said lower surface is adjacent said head of said anchor member, wherein said pair of opposed substantially flat external surfaces are received in said longitudinal aperture adjacent said pair of opposed substantially flat walls of said receiver member;
• and
• a retaining member at least partially within said groove and around at least a portion of said anchor member;
• and
• wherein said longitudinal aperture in said receiver member extends along a second longitudinal axis, said pair of opposed substantially flat walls in said lower portion of said aperture arranged generally parallel with said second longitudinal axis, said pair of opposite substantially flat external surfaces of said crown member and said flat portion of said bone anchor member also arranged generally parallel with said second longitudinal axis.

An orthopedic medical apparatus, comprising:

• a receiver member having an internal chamber with at least one substantially flat wall;
• a crown member at least partially in said chamber, said crown member having a rounded lower surface, a substantially flat external side surface, and an opening extending laterally through said substantially flat external side surface;
• and
• a bone anchor member having a longitudinal axis and head portion with at least one substantially flat wall portion, said head portion being adjacent said rounded lower surface of said crown member, said substantially flat wall portion of said anchor member being substantially parallel to said longitudinal axis and positioned at said opening in said crown member and adjacent said substantially flat wall of said receiver member, wherein said anchor member is limited to pivotal movement with respect to said receiver member in a single plane;
• and
• wherein said longitudinal aperture in said receiver member extends along a second longitudinal axis, said pair of opposed substantially flat walls in said lower portion of said aperture arranged generally parallel with said second longitudinal axis, said pair of opposite substantially flat external surfaces of said crown member and said substantially flat wall portion of said anchor member also arranged generally parallel with said second longitudinal axis.