each of these two movements could have been achieved by a single muscle connected to the middle of the thyroid. rather each of them was created in pairs so that if something happened to one of them that would invalidate its movement the other would take its place.
وقد كان يمكن حصول كل واحدة من هاتين الحركتين بعضلة واحدة تتصل بوسط الدرقي. وإنما خلق لكل واحدة منها زوج ليكون إذا عرض لإحداهما ما يبطل حركتها قامت الأخرى مقامها.