"tilted downward" is correct and can be used in written English.
For example, you could use it in a sentence such as "The airplane's wings were tilted downward as it descended."
The face, tilted downward, has no eyes as if the character was blind.
After each paroxysm, he paced, hands behind his back, head tilted downward.
After the lava cooled, the basalt layer cracked into faults and tilted downward toward the east.
As Ms. Prunty delivered her opening statement, Mr. Williams sat slouched in his chair, with his head tilted downward.
My address was a tall, narrow Victorian with a second-level porch that tilted downward as if it might fall off; the house was deep, Pepto-Bismol pink.
His Lili is like a nervous young swan with his head tilted downward, his long neck always visible, his fingers fluttering and a shy smile on his face.
On a down wave, the wings sink and tilt downward, pulling the craft forward.
The plateau's surface is higher in the southeast and tilts downward toward the northeast.
In Nantucket's Whaling Museum, the skeleton of a sperm whale hangs from the wave-shaped ceiling, its massive head and jaw tilting downward as if it has just dived beneath the surface.
A gannet's skull is built like the nose of a Concorde: strong, delicate, unpierced, and able to tilt downward on landing but hold straight ahead when passing at great speed through the water.
Conclusions: The scapula normally tilts downward with or without stroke.
