Level 1 contains the submental and submandibular nodes 2. Level 4 is defined superiorly by the omohyoid muscle and inferiorly by the clavicle 5. Level 5 contains the posterior cervical triangle nodes 6. Larger tumors have a greater likelihood of cervical spread 2. Pharyngeal lesions tend to metastasize more frequently than those in the oral cavity or larynx B. Detection 1.
Body habitus influences the ability to detect metastasis iii.
Preoperative radiation therapy decreases the sensitivity of neck palpation according to some authors 2. Central lucency was once considered pathognomonic of necrotic tumor, whereas recent reports describe similar findings with fatty inclusions within nodes as well as in small arteries with intralumenal plaques iv. Other criteria such as morphology, and grouping of nodes may enhance detection, but definitive studies are required v. This recent evidence calls into question the necessity of routine neck scanning in all head and neck cancer patients B. Prognostic implications 1. The number of involved nodes significantly impacts on survival with involvement of two or more nodes carrying a much higher incidence of distant metastasis C. Location of spread 1. The work of Lindberg, Shah, and Byers indicate that the lymphatic drainage of the upper aerodigestive tract occurs along predictable pathways a.