Former Formula One driver Alex Zanardi remains in a serious but stable condition following Friday's accident in a hand bike relay.
The four-time Paralympic hand cycling gold medallist suffered head injuries in a crash with a lorry in Pienza.
Zanardi underwent surgery at hospital in Siena, and remains on a ventilator in intensive care.
A hospital statement issued on Monday morning read: "Alex Zanardi remains stable. The third night of his ICU stay passed without variations.
"The clinical conditions therefore remain unchanged, while the neurological picture remains serious.
"The multi-disciplinary team that takes care of him will evaluate in the next few days any diagnostic-therapeutic actions which are to be taken."
Zanardi, 53, had both legs amputated after a crash in the American Memorial 500 Cart race in Germany in 2001.
PA
