When I was studying in Xi'an in 1996, the winter was terrible (still is) and I ate a lot of 西安羊肉泡馍 (xī ān yáng ròu pào mó) which is lamb / mutton soup with hand torn pitta-like bread. The restaurant nearest my residence made it with lamb neck.
The internet has many recipes but I've never found one that uses neck, but I always do in tribute to the place that kept me from freezing to death!