出自《晏子春秋·内篇杂下》，肩擦着肩，脚跟碰着脚跟。常用来形容人非常多，特别拥挤。摩：擦。踵：脚后跟。有时也作“踵接肩摩”、“肩摩踵接”或“肩比踵接”。
This phrase comes from the Inner Miscellaneous Section of the Yanzi Chronicles, describing people so numerous that their shoulders rub together and their heels kick one another’s – used to depict extremely crowded situations. “摩” means to rub, while “踵” refers to the heel of the foot.
春秋时期，齐国的丞相晏子奉命出使楚国。
During the Spring and Autumn Period, the minister Yanzi of the State of Qi was dispatched on a diplomatic mission to the State of Chu.
楚王听说晏子的身材不高，有意想羞辱一下他，便派人在城门边上挖了一个狗洞。晏子到来时，发现楚国都城大门紧闭，只有城门边上的狗洞可以进城。他知道这是楚王故意羞辱他，于是说道：“齐国派我到楚国出使，没想到我走错了地方，竟然来到狗国了！”楚王听后，只得命令打开城门迎接晏子。
The Chu king, hearing that Yanzi was not very tall, intentionally tried to insult him by having his men dig a small dog tunnel next to the city gate. When Yanzi arrived, he found the main gate closed, with only the dog tunnel providing entry. Realizing this was the Chu king’s deliberate insult, Yanzi remarked: “The State of Qi sent me as an envoy to Chu, but it seems I’ve come to the wrong place – the State of Dogs!” Hearing this, the embarrassed Chu king had no choice but to open the main gate to receive Yanzi.
楚王的阴谋不但没有得逞，还反被人家羞辱一番，所以楚王觉得很没面子，总想找机会报仇。在楚国的王宫中，楚王看着个子矮小的晏子，问道：“你们楚国没有人才了吗，怎么会派你这个相貌丑陋、身材矮小的人到楚国来呢？”
The Chu king’s plot had not only failed but backfired into humiliation for himself. Feeling resentful, he sought an opportunity to get revenge. In the palace, looking at Yanzi’s short stature, the Chu king mocked: “Has the State of Qi run out of talented people, that you, an ugly and stunted man, were sent as an envoy?”
晏子反唇相讥道：“在我们齐国都城临淄的街道上，人们把衣袖张开就能遮住太阳，一挥汗就像天上下雨一样，街上的行人肩擦着肩，脚跟碰着脚跟。可以说，我们齐国到处都是人才。可是大王不知道，我们国家有一条规定，那就是有本领的臣子出使贤明君主的国家，无能的臣子只能去无能之君的国家。我相貌平平，而且又没有什么才能，所以只能到楚国来了。”楚王本想捉弄晏子，结果却被晏子戏弄了一番。
Yanzi retorted cleverly: “In the streets of Linzi, the capital of Qi, people can shield the sun simply by opening their sleeves. Shaking off sweat is like rain pouring from the sky. Pedestrians brush shoulders and kick heels. Truly our State of Qi is brimming with talent everywhere. But you may not know, my lord, that our state has a rule: talented ministers are sent to enlightened rulers, while mediocre ones can only be sent to inept rulers. With my unremarkable appearance and lacking any special ability, I could only be sent to Chu.” What was meant as an insult was deftly turned back on the Chu king by Yanzi’s wit.