Honestly, it makes me think of the proprioceptive system. I could be wrong about this, but it came up once during a neurosurgery examination, the subject of Proprioception. That is what's also called kinesthesia, which is "the body's ability to sense its position, movement, and action. It allows people to know where their body parts are without looking, and how they relate to each other. This helps with coordination and allows people to walk without thinking about where to put their feet, or touch their elbows while blindfolded. Proprioception also helps people determine how much force to use when lifting, pushing, pulling, or holding objects."

I literally copy/pasted that from Google AI. When I had my molars removed (they were all cracked) one by one, it was normal for me to lose track of where my tongue and/or cheek was, when the numbing medicine was still working. For that reason dentists sometimes tell us we can't eat anything for so many hours, they don't want us to chomp a nice big hunk of our own interior cheek. I remember biting my tongue as a kid because I had to have a bunch of teeth removed then too.

I believe it has to do with your nervous system, our proprioception of where all out own body parts are. When you talk about your C spine having issues, seems a good question for a Neurologist or Neurosurgeon.