Story highlights A six-inch screw pierced a boy's skull, right between the brain's two hemispheres

The boy was "a millimeter away" from bleeding to death, his neurosurgeon said

(CNN) A freak accident nearly took the life of a 13-year-old Maryland boy last weekend when a 6-inch screw entered his skull, his family and doctor told CNN.

Darius Foreman was building a treehouse Saturday when he fell from a branch, knocking over a five-foot-long wooden board, which came down on top of his head, his mother Joy Ellingsworth recounted.

An X-ray from Johns Hopkins Hospital, where the boy was airlifted, shows a portion of the screw lodged right between the two halves of the brain -- threatening to tear the largest channel that drains blood and other fluids from the brain. Injury to this part of the brain could have been "catastrophic," according to his surgeon, Dr. Alan Cohen.

"He was a millimeter away from having himself bleed to death," Cohen, chief of pediatric neurosurgery at Johns Hopkins, told CNN.

"I absolutely panicked," Ellingsworth said. "It was very scary, one of the scariest things I've ever been through."

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