It’s the placenta, it’s distorts the ultrasound. My girl looked good on some and scary on others x
Could be his other hand or the umbilical cord, too.
I think it’s just the way the image comes out! My baby was moving his hand in one of the scans and it looked scary but all the other scans are fine. Id say dont pay too much attention to the details of a 3d scan, just the general picture x
I’d say just wait and see until he’s born! Although 3D scans are great babies do tend to look more lumpy and bumpy in them :)