The 46-year-old was surfing with his son in south of Brisbane and said on his Instagram account on Saturday that he came off second best with a "Straddie back bank" and that it was "game over for a few days".
He posted a second message on Sunday with a photograph of him in a neck brace and nasty abrasions on his forehead.
"Fractured C6, torn C5, C4 ligaments safe to say I truly have dodged a bullet," he wrote referring to injuries to his cervical vertebrae.
"Just wanted to say a big thank you to all our mates on Straddie (Stradbroke Island) who have been so supportive.
"Thank you everyone. On the road to recovery."
The burly Hayden retired in 2009 as one of cricket's leading opening batsmen, scoring 8625 runs with 30 centuries from 103 tests at an average of 50.73.
He held the world record score for a test innings with his knock of 380 against Zimbabwe in October 2003 before West Indies great Brian Lara surpassed it with 400 not out six months later.
Hayden also formed a formidable opening partnership with current Australia coach Justin Langer, combining for 5655 test runs as an opening pair, which is second only to the vaunted West Indies duo of Gordon Greenidge and Desmond Haynes, who accumulated 6482 runs at the top of the batting order.
(Reporting by Greg Stutchbury; Editing by Sudipto Ganguly)
