Could my baby have spina bifida occulta?

I have a 10 month old baby boy, he is a good boy never cries, very playfull always happy, he sleeps well. he started crawling at 7 months, he starting standing up by himself at 8 months, he is now starting to do little steps, so anytime he will start walking. My concern is that he has a sacred dimple in his above is . Doctor said he wasent concerned abou it. So about a month ago i was touching my sons spinal cord i noticed his that there gap in his mid back and i feel no bone (spinous process) then you go down alittle and then the spinal cord continues to his tailbone. Its had to explain, basicaly i follow his spinal cord from top to bottom with my finger and when i get to his mid spinal cord i feel like a hole or gap then you go alittle bit down and then you start feeling the bones again but really sharp and boney. I dont know what this is, i have touched my nephews and neices backs and they have nothing like that. Its like if my babiy was missing a spinous process. Has any one heard anything similar to this? I did some research and the only close thing i cant find is spina bifida occulta. But i dont think he has that because he has no issuses with his back. He will be seeing his doctor in 2 month i will ask him.