Italian media reports said a CT scan was clear but Ospina will remain under observation for the next 24-48 hours. The club have stated via social media that Ospina due to hypertension or 'shock' after the earlier collision caused internal blood loss.
Carlo Ancelotti's side were pegged back after taking a two-goal lead in the first half, but pulled away after the break to reduce Juventus' lead at the top of Serie A to 15 points.
Amin Younes’ curled finish on his first start of the season gave Napoli an early lead before Jose Callejon doubled their advantage with a bundled finish.
Udinese responded in impressive fashion as Kevin Lasagna’s strike got them back in the game on the half-hour before Seko Fofana drove a finish past Ospina to draw the visitors level.
Arkadiusz Milik headed Napoli back in front from a corner in the second half and Dries Mertens made sure of the points as he darted inside and found the net with 20 minutes remaining.
Earlier, Lazio thrashed Parma 4-1 in Rome and relegation-threatened Empoli recorded a vital 2-1 win over second-bottom rivals Frosinone, while bottom side Chievo produced a shock by holding European hopefuls Atalanta to a 1-1 draw in Bergamo.