After months of physical therapy, he was finally able to mobilize his arm.

mobilize 是动词，由词根 mob-（移动）和后缀 -ize（使...化）组成，字面意思是"使能够移动"。在这里指"使（手臂）恢复活动能力"。 mobilize 在医疗康复语境中特指"通过治疗恢复肢体活动功能"。