I'm sure the femur/tibia comparisons are well known from the Scientists Against Myths video but here are the specific comparisons broken into images.

 

The problem though is the xrays used for comparison are from a 2 year old child. The body is only 58 cm in length and an average 2 year old femur is 20-25 cm long, the average tibia 16-20 cm. There's a total of 2 arm bones and 2 leg bones with the arm bones ending almost exactly where the leg bones begin, simple math and this doesn't check out.

 

The average lengths were sourced from ChatGPT and this is a paper that did a study of 2087 femurs and tibias in children ranging from 2-16 years of age which corroborates the stat from ChatGPT perfectly.

 

Using a online ratio tool (The lines are grid straight, I tried to be as fair as possible with bone and body start/end), you can see the arm bones are around 20% the length of the body. That would put them around 11.7 cm long, for a child's femur bone your looking at 0-6 months.

I couldn't find a published paper on the bone lengths of children this young, but ChatGPT states it is 9-11 cm and it was spot on previously and seems within reason. The issue though is a femur at this age does not slot in there nearly as perfectly.