Book 4 - Self Instructional Manual for Cancer Registrars - SEER ...

PharynxThe pharynx is divided into three regions: the nasopharynx, the oropharynx, and the hypopharynx(laryngopharynx).The nasopharynx lies behind the nasal cavities, above the soft palate, and below the base of theskull. The oropharynx lies behind the buccal cavity, below the soft palate, and above the opening tothe larynx. The hypopharynx (laryngopharynx) is located behind, lateral and inferior to the larynx.The nasopharynx has been discussed in detail in Section F, The Respiratory System.The pharynx (throat) serves as a passageway for the respiratory and digestive tracts, since air mustpass through this structure before reaching the lungs, and food must pass through it to get to thestomach. The pharynx is also important for phonation because by changing its shape the differentvowel sounds are formed. The pharynx is made of muscle which is lined with mucous membrane.Embedded within this muscle are the palatine and pharyngeal tonsils. The tonsils are composed oflymphoid tissue and may be considered part of the lymphatic system. However, they are locatedwithin the respiratory and digestive systems. The adenoids or pharyngeal tonsils are located in thenasopharynx. The faucial or palatine tonsils are located in the oropharynx. (The lingual tonsils, aswe have learned, are in the base of the tongue. It is the palatine tonsils that are commonly removedby a tonsillectomy.)The lymphatics for the pharynx drain into the cervical lymph nodes, namely, the internal jugular(upper and lower deep cervical), and retropharyngeal lymph nodes. The blood supply is via theexternal carotid arteries and internal jugular veins.Figure 29. OROPHARYNX AND HYPOPHARY'NX-_jCho&na193