The ability to estimate the size of lesions accurately is an important skill in pathology. Often people lack a good sense of small sizes in the metric system. Students may be comfortable with "guesstimating" the length of a mass to be, say, two inches, but when asked how many centimeters that is they will often guess seven or eight when really it is closer to five centimeters.
To eliminate this "guesstimating" problem, it is best to pick a readily accessible (and socially acceptable) part of your body such as the length of a phalanx of your index finger or the width of your thumb. Measure this part of your body with a metric ruler.
The example at right is to scale. The ruler in the photo is actually 3 cm long, so you can hold up your finger to the screen now and measure the approximate length of part of your finger.
Memorize this number and then whenever you need to measure a lesion, you can simply pull out your handy-dandy finger and use your pre-measured digit as a mini-ruler.
A few examples are presented in this section for you, but you will get more practice in the "Practice Questions" section.
