A 15-month-old US boy has survived an 11-storey fall from a balcony at his parents' apartment in Minneapolis in Minnesota.

Musa Dayib has been nicknamed "the miracle baby" after escaping death despite slipping through the railing and making a perilous fall.

In addition to fractures to both his arms, his backbone and his ribs, the boy also suffered a concussion and is breathing through a ventilator. 

He is in a critical but stable condition, but is expected to survive.

The boy was apparently saved by his soft landing on a mulched area.

"If you and I fell that far, we would be dead," Tina Slusher said from the paediatric intensive care unit at Hennepin County Medical Center.

"He's a baby and ... they tend to be more flexible and pliable than you and I would be.

"Having said that, it's a real gift from God that he made it because this is a huge fall."

Local media said the boy, from the large Somali American community of Minneapolis, fell from his family's balcony around 8pm on Sunday (2am Irish time).

"When people found out he survived, no one could believe it," said local community activist Abdirizak Bihi, who spent time at the hospital with the family on Monday.

The apartment building's owners and managers said the balcony had passed inspection when the 1,303-unit Riverside Plaza underwent a major renovation in 2011-2012.