17. =Thoracic Portion of Oesophagus.= Note size (stenosis, dilatation, diverticulum), contents (food, stomach-contents, blood, pus, foreign-body), thickness of wall, color of mucosa (normally grayish-white), neoplasms (carcinoma), perforations, erosions (aneurism, abscess, neoplasm), inflammation. Anomalies, tuberculosis, syphilis, actinomycosis and neoplasms (with the exception of carcinoma) are rare. The most common location of carcinoma is toward the cardia. Thrush is the most common parasite. Varices of the œsophageal veins are common, and from these fatal hemorrhages may occur. In the thoracic portion they are usually the result of collateral distention to offset a portal stasis (hepatic cirrhosis, Banti’s disease, thrombosis of splenic or portal veins). The passage of stomach-contents through the cardia into the œsophagus may cause a postmortem softening or perforation of the œsophageal wall. 18. =Thoracic Duct.= Note size, contents and character of wall. Tuberculosis, malignant neoplasms, obstruction, rupture and purulent inflammations are the most important pathologic conditions. In miliary tuberculosis the thoracic duct may be the primary focus or the avenue by which the bacilli enter the blood. The duct also plays an important part in the dissemination of malignant tumors and infections from the abdominal cavity and pelvis. Chylothorax and chylopericardium are usually caused by the blocking of the thoracic duct by malignant neoplasms (lymphosarcoma, carcinoma), or by rupture of the duct. 19. =Thoracic Vertebrae.= Note surfaces of vertebræ (normally smooth), curvatures, softening, erosions, exostoses, neoplasms, fractures, dislocations. Tuberculosis, curvatures and malignant tumors (secondary carcinoma, primary sarcoma, myeloma, chloroma) are the most common conditions. Aneurismal erosions are not rare. CHAPTER IX. EXAMINATION OF THE MOUTH AND NECK. I. METHODS OF EXAMINATION.