The long-scale calliper is a tool developed by the orthotic laboratory where it is used for the realization of orthotic devices for the trunk and for the limbs. A sliding ring has been added and a plumb bob is added onto it and the calliper shows the asymmetries of the trunk in a clear value and this allows comparison between the future measurements.
During a visit for the rachis the calliper allows the quantification of the asymmetries in the alignment at the frontal plane and in particular it permits to assign a value to the asymmetries at the frontal plane and in particular, it allows to assess the displacement of the head, of the upper part of the trunk and of the sides regarding the centre-line, taking as a reference for this purpose, the gluteal cleft or the bisector at the base. A side shift of the centre-line of the head is defined as imbalance, a shift of the centre-line of the shoulders or the sides is defined as translation.
The change of position can be represented in absolute figures (cm) o in a percentage (% of translation) the latter is advisable when the patient is still in a period of growth to state the anthropometric changes of the trunk.
To make the calculation of the percentage of translation easy a simple chart with two columns is available along with the tool. This chart indicates with a single figure how much, in percent, the center of the segment involved in the measurement is shifted to one side is regarding the theoretical symmetry center.
