Lewis & Short

cernŭo, āvi, ātum, 1, v. a. and n. [cernuus], to throw or fall head foremost (only ante- and post-class.), Varr. ap. Non. p. 21, 8; App. M. 1, 19, p. 111, 9; Front. Princ. Hist. 5.
In dep. form: tigres cernuantur, Sol. 17: equus de industriā cernuatus, id. 45.