What part of the deltoid is worked in a one arm dumbbell row?

In a one-arm dumbbell row, the primary focus is on the muscles of the back, particularly the latissimus dorsi. However, the rear (posterior) deltoid also gets some activation during this exercise as it helps stabilize the shoulder joint and assist in pulling the weight. While the posterior deltoid is involved, the primary emphasis remains on the back muscles rather than the shoulders.