I've also been wondering about this topic. I fell on a bottle (Snapple - non alcoholic) when skating as a teenager and developed a nerve entrapment. Went through countless doctor visits for a diagnosis, only happened after being referred to a specialist after severe clawing (2 fingers of ulnar nerve being stuck towards palm) which caused me a lot of trouble in rehabilitation and took away from work exp & research.
But through recovering I've been intrigued by medical technologies and became one of the reasons for my grad studies pursuit (along with wanting to teach higher education). So I don't know if I should include it in my SOP, I'm hinging on relevance but I don't know many others in the same situation. I've recuperated in strength, and even though feelings mostly lost it shouldn't impinge my studies, anymore that is.
Anyway, I've read that a lack in any area of expectancy should be explained in the SOP, so I've included my experiences in my essays (also history) which ties both of them together but I'm not totally sure. My family's on board, but no one in my family went to grad school, in engineering that is.