3 year old check up

My daughter had her check up with the paediatrician yesterday and as he was feeling her abdomen he said he could feel her spleen tip. He’s ordered an ultrasound of the spleen and liver but said he wasn’t too concerned. But me as an anxious mom am worried sick. My husband says if doc isn’t concerned then it’s likely not too much of a worry.

She does have delayed gross motor skills with walking, she actually didn’t start walking until she was 2.5 years old and has slightly poor muscle tone in her legs and hyper mobility in her joints. Other than that she is improving slowly but surely.

So back to this whole spleen tip thing. Anyone else have this with their child? What turned out to be the cause for you?