To build a perfect jacket I must know your 'anatomic' measures (that is, measured on the naked body taking care of keeping the measuring tape close and tight to the body).
Circumference's measures are the most important and the chest one, halved, determines your size (ie. chest 88 cm > size 44). Each size is paired with ideal measures of breast circumference, waistline and hips (see the table of anatomic measures).Actually, only a handful of lucky people have a perfect size (with real measures corresponding to the ones in the table). Making a practical example, a woman can have a size 44 (half chest measure) but a waist line of size 48. Because of that, in order to have a garment that fits well, it is necessary a custom tailoring.
While crafting a jacket, it the tailor's duty to add some centimeters of wearability. In the sartorial lexicon with 'wearability' we mean that added value to the anatomical measures to give the garment more comfort and flexibility. This added value is determined by the chosen model, the characteristics of the textile used, and the personal way of dressing up (there are those who prefer tight garments and those who favour comfortable ones).
This is the first and the most important measure to take, as it determines the size (size=half chest measure: eg. size 44 means chest circumference of 88cm). It is measured by passing around the chest the measuring tape, tight and sticked to the body, under the armpits.
It is measured by passing around the tape at the greatest circumference of the breast.
Waist Line Circumference
It is determined by passing around the tape at the narrowest point of the wast line, as the photo shows.
It is the vertical measure that start from the shoulder to the greatest circumference of the breast, as the photo shows (it is an optional measure, but in some jacket models it can be very handy).
Front Waist Line Height
It is the measure that is obtained positioning the tape from the shoulder to the waist line point going across the greatest circumference of the breast, as the photo shows (optional measure but essential in tight line jackets).
It is a measure that is helpful only in particular cases, it is always measured in the upper part of the arm.
It is always measured on the back, as the photo shows, and it is the distance between the two most prominent points of the houlders. It is a very important value as it determines the width of the back.
The photo shows the correct way of how to measure the length of the sleeves that is sought after. It is measured by positioning the tape at the end of the shoulder - the collarbone – and, when tight, it goes across the arm with a 90°-bent elbow until the fixed length point.