Measuring Rule

Sources: A Manual Of Peroral Endoscopy And Laryngeal Surgery

It is customary to locate esophageal

lesions by denoting their distance from the incisor teeth. This is

readily done by measuring the distance from the proximal end of the

esophagoscope to the upper incisor teeth, or in their absence, to the

upper alveolar process, and subtracting this measurement from the

known length of the tube. Thus, if an esophagoscope 45 cm. long be

introduced and we find that the distance from the incisor teeth to the

ocular end of the esophagoscope as measured by the rule is 20 cm., we

subtract this 20 cm. from the total length of the esophagoscope (45

cm.) and then know that the distal end of the tube is 25 cm. from the

incisor teeth. Graduation marks on the tube have been used, but are


[FIG. 7.--Measuring rule for gauging in centimeters the depth of any

location by subtraction of the length of the uninserted portion of the

esophagoscope or bronchoscope. This is preferable to graduations

marked on the tubes, though the tubes can be marked with a scale if