Complex sentence: Each straight flush is uniquely determined by its highest-ranking card; and these ranks go from 5 (A- 2-3-4-5) up to A (10-J-Q-K-A) in each of the 4 suits.
Split into simpler sentences: Each straight flush is uniquely determined by its highest-ranking card. These ranks go from 5 (A- 2-3-4-5) up to A (10-J-Q-K-A) in each of the 4 suits.