Proprioception: Some Tired Old Notions

Proprioception has been defined as 'the aspect of inner sensing that lets you know where you are in space.' Close your eyes and extend your arm straight out. You know about where your hand is, right? Now bend your elbow – your hand will come closer to your face, and you'll feel that, too, even with your eyes closed. By gauging the stresses and strains on your muscles, fascia, joints, tendons – all that good nervous system stuff – you nimbly calculate the position of your limbs, torso, head and middle left toe.

Proprioception also has been defined as 'that which relies on proprioceptors'. Which isn't as entirely circular and stupid as it sounds. But almost. It's just another way to say 'measuring the stresses and strains of gravity and movement.'

A third bit of 20th century thinking was that proprioception takes place in the muscles, tendons and ligaments and is analyzed by the brain. True, but so much more proprioceptive signaling takes place in the fascia. (And the fascia has so many other interesting jobs at the same time!) And some analysis happens outside the brain.

So… 21st century? Proprioception is a subset of interoception that makes use of stresses, strains, movement and gravity. Other data streams also contribute to our sense of where we are in relation to gravity and the world. The integration of that rich information happens up and down and all around ('afferent' and 'efferent') and the analysis does not all happen in the brain.