28. The assembly of claim 27 , wherein the rod portion includes a plurality of substantially stiff, and longitudinally extending rodlets.
27. A medical implant assembly having two bone attachment structures cooperating with a dynamic longitudinal connecting member, wherein the assembly comprises: a) the connecting member, the connecting member comprises: i) a first end, a transition portion and a second end; ii) a rod portion extending longitudinally from the first end to the transition portion along a longitudinal axis and running substantially parallel with the longitudinal axis; iii) a tensionable cord portion joined with the rod portion and extending from the transition portion to the second end; and iv) a substantially elastic spacer covering the rod and cord portions.