My 4 month baby boy's left rib feels small harder at that place.. and he has no pain. he is actve..is it normal?

A. The protruding out of the lower ribs in your child may be due to a Vitamin D deficiency or calcium deficiency. For diagnosis, you can get his serum Vitamin D 3 levels, serum calcium levels and serum alkaline phosphatase levels estimated. The treatment involves adequate supplementation according to the deficiency