Head and neck cancers are tumors that start in the squamous cells that line the mucosal surfaces of the head and neck (for example, those inside the mouth, throat, and voice box). Squamous cell carcinomas of the head and neck are the name given to these tumors. Head and neck cancers can also start in the salivary glands, sinuses, muscles, or nerves, but these types of cancer are significantly less prevalent than squamous cell carcinomas.