Res Yudikata shows how to make a reversible FK chain in Maya for spines and other tasks.
Check out this tutorial from Res Yudikata that shows how you can create a reversible FK set up in Maya, where each end can be open-ended. The setup is a common one for spines and other rigging tasks.
Yudikata also offers a script that you can download and instantly create the setup shown in the tutorial. Check that out here.
Res Yudikata is a Rigging Supervisor at Infinite Frameworks Studios.