ISO 8548-2:2020 Prosthetics and orthotics — Limb deficiencies — Part 2: Method of describing lower limb amputation stumps.
5 Measurement of lower limb amputation stumps
5.1 Reference levels and reference planes
5.1.1 General
Identify the reference levels and planes relevant to the particular level of amputation as described in
5.1.2 and 5.1.3.
5.1.2 Reference levels
5.1.2.1 Waist
The level midway between the costal margin and the iliac crest.
5.1.2.2 Iliac crest
The level defined by a line joining the highest point on the crest of each ilium.
5.1.2.3 Proximal
The most proximal level at which a circumferential measurement, perpendicular to the mid-line of the
thigh, can be obtained.
5.1.2.4 Minimum circumferential
In knee and ankle disarticulation stumps only, the level of the minimum circumference.
5.1.2.5 Femoral condylar
In knee disarticulation and transcondylar amputation stumps only, the level of the maximum condylar
circumference.
5.1.2.6  Inflection
In transfemoral and transtibial stumps only, the level on the stump at which the slope of the stump
shape changes as it curves in towards the end.
5.1.2.7 Stump end
The level of the stump end.
5.1.2.8 Medial joint line
The level of the medial tibial plateau, unless there is a fixed deformity of the knee, in which case this level is the highest at which a circumferential measurement perpendicular to the mid-line of the stump can be obtained.
5.1.2.9 Mid-patellar tendon
The level mid-way between the origin and insertion of the patellar tendon.
5.1.2.10 Malleolar
In ankle disarticulation stumps only, the level of the maximum distal circumference.
5.1.2.11 Ground
The level on which the patient is standing barefoot.
5.1.3 Reference planes used for partial foot amputations
5.1.3.1 Heel
The plane at the posterior aspect of the heel parallel with the mid-line of the leg.
5.1.3.2 Anterior tibial
The plane at the anterior aspect of the tibia at the ankle joint line parallel with the mid-line of the leg.
5.1.3.3 Stump end
The plane at the stump end parallel with the mid-line of the leg.
5.1.3.4 Toe
The plane at the tips of the toes of the contralateral leg parallel with the mid-line of the leg.
ISO 8548-2 pdf download.