Which movement of the maxilla causes the greatest widening of the alar base?

The movement of the maxilla that causes the greatest widening of the alar base is anterior movement. When the maxilla moves forward, it directly influences the soft and hard tissue surrounding the nasal structures. This forward repositioning allows for increased separation of the maxillary bones and subsequently affects the width of the nasal base, expanding the alar region.

In contrast, posterior movement tends to retract the maxilla, which may not promote the widening of the alar base effectively. Vertical movement primarily affects the height of the maxilla rather than its width, as it does not significantly alter the lateral dimensions of the nasal structure. Lateral movement may provide some degree of widening, but it does not achieve the same level of effect as anterior movement in terms of expanding the nasal base.

Overall, the anterior movement of the maxilla plays a crucial role in enlarging the alar base by allowing the surrounding anatomical structures to move outward, resulting in a wider nasal aperture.