The 34-year-old, who has announced she will retire after the championships in Are, Sweden, went down hard, but was able to ski down after receiving medical attention.
Vonn misread a bump high up the hard-packed course that pitched her forwards into a pole and then slid into the safety netting.
Medical staff were quickly on the scene to help her get gingerly back to her feet, to applause from the crowd around the finish line.
No sooner had the commentator announced that Vonn had form on the hill, having won two world silver medals in Are in 2007, than her skis kicked back off the rise to groans from the crowd.
Race leader Mikaela Shiffrin was shown on the big screen television clutching her head as her teammate, who is just four wins short of Ingemar Stenmark's World Cup record of 86, slid out at pace into the bright red netting.
It was a case of deja vu for Vonn, who suffered a season-ending injury in the opening super-G of the 2013 world championships in Schladming.
Vonn will bow out after Are after 19 illustrious seasons that have seen her scoop a record 20 crystal globes, including four overall titles. She is also the 2010 Olympic downhill gold, and won the world speed double in Val d'Isere in 2009.
As injuries continued to take their toll, Vonn announced last week that "I have finally accepted that I cannot continue ski racing... My body is broken beyond repair and it isn't letting me have the final season I dreamed of".