he said the shoulder tapers on the lateral side and becomes thick. as for its thinness it is because the place where protection is needed there is small and the place of the rest of its parts is not like that. as for its thickness it is so that it is strong so that the hand joint can be created in it. as for the increased thickness of its two ends it is for the sake of the depression in it so that its place is wide.
قوله والكتف يستدق من الجانب الوحشي، ويغلظ. أما دقته فلأن الموضع المحتاج فيه هناك إلى الوقاية صغير، ولا كذلك موضع باقي أجزائه وأما غلظه فليكون قويا ليمكن أن يخلق فيه مفصل اليد، وأما زيادة ثخانة طرفيه فلأجل النقرة التي فيه ليكون مكانها متسعا.