The skeleton was uncovered in an area of new excavations, close to a newly-discovered alleyway of houses with balconies.
Massimo Osanna, the director general of the archaeological site, called the discovery "dramatic and exceptional".
"A formidable stone block (perhaps a door jamb), violently thrown by the volcanic cloud, collided with his upper body, crushing the highest part of the thorax and yet-to-be-identified head, which probably lies under the stone block," archeologists said.
The experts found lesions on his tibia which indicate a serious bone infection.
That "could have caused significant walking difficulties, enough to impede the man's escape at the first dramatic signs which preceded the eruption," they said.
Earlier this month, archeologists made another unusual discovery – the carbonised remains of a horse which died during the eruption of Vesuvius.
The horse was found in the remains of a large Roman villa, which tomb raiders had been excavating illegally in search of artefacts and valuables.
By pumping plaster into the space where the horse was found, experts produced an accurate cast of the animal.
It was the first time that a cast was made of a horse at Pompeii – the technique has previously been used for the human victims of the cataclysmic eruption.
Experts believe the horse was used in military parades and ceremonies.
It was found in the remains of a stable attached to the villa.
