Classification criteria of TNM 6th and TNM 7th staging system for nasopharyngeal carcinoma.

Abbreviations: UICC = the International Union Against Cancer; AJCC = American Joint Committee on CanceraMasticator space involvement denotes extension of tumor beyond the anterior surface of the lateral pterygoid muscle or lateral extension beyond the posterolateral wall of the maxillary antrum and the pterygomaxillary fissrue.bMasticator space primarily consists of the muscles of mastication. Anatomically, the superficial layer of the deep cervical fascia splits to enclose the muscles of mastication to enclose this space. These muscles are the medial and lateral pterygoid, masseter and temporalis.Classification criteria of TNM 6th and TNM 7th staging system for nasopharyngeal carcinoma.