MERU DANDA:

Thumb straight like thumbs up, and the other fingers folded touching the palm. The hands rests on the thighs. This Mudra energises the entire autonomous system and spinal cord – which is massaged well, making the pranic energy flow well. All spinal problems can be handled with this Mudra.
You can combine doing the Mudra with pranayama. Do the breathing with the following count: inhale for four counts, hold for one count, exhale for five counts and hold for one count. Do this 40 to 50 times in the morning. Entire spinal cord will be strengthened.
Sympathetic nervous system controls all the organs. Then the entire system is energised and our stress level gets to zero.
Do the Mudra when you are tired. Direct the prana (visualising) to the spinal cord, while doing the pranayama.
Vallabam Gajaananam Eka Thandham
This mantra along with Meru Mudra is good for the spinal cord. It drives out our insecurity also. If you chant regularly, your back will become solid and strengthened.