You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Killian's dehiscence is in and explain in detail?
Inferior constrictor muscle has two parts. 
Thyropharyngeus with oblique fibres and cricopharyngeus with transverse fibres.
Between these two parts exists a potential gap called "Killian's dehiscence". It is also called "Gateway of tears". 
This is also the site of herniation of pharyngeal mucosa in case of the pharyngeal pouch.