He received immediate medical treatment after the accident to prevent further complications.

medical 来自名词 medicine（医学），加形容词后缀 -al 构成形容词，意思是"医学的、医疗的"。 treatment 是名词，来自动词 treat（治疗、处理），意思是"治疗、处理"。medical treatment 指"医疗治疗"，即由专业医务人员进行的治疗措施。