A man craning his neck to see if a train was arriving at a West Village subway platform yesterday was smacked in the head by the approaching train and knocked to the ground, authorities said.

The 57-year-old victim was in critical condition after being hit by the uptown 2 train at the West 14th Street station at 4:10 p.m., cops said.

The impact, which partially tore flesh from his face, sent the victim flying backward into the platform where straphangers found him semi-conscious, witnesses said.

“His hand was twitching a little, he was lying on his side,” said a Post staffer who witnessed the aftermath of the tragedy.

“He tried to push himself up. We told him to stay down and he said, ‘OK, OK.’ “