Quantitative study of the popliteal fossa in the human foetus.

The popliteal fossa presents an extensive diamond-shaped topographical element on the posterior aspect of the knee. With the use of classical anatomical dissection, digital image analysis of NIS Elements AR 3.0, and statistics, we morphometrically analysed the size of the popliteal fossa in human foetuses aged 17-29 weeks of gestation. Morphometric parameters of the popliteal fossa increased logarithmically with foetal age: y = -44.421 + 24.301 × ln (age) for length of superomedial boundary, y = -41.379 + 22.777 × ln (age) for length of superolateral boundary, y = -39.019 + 20.981 × ln (age) for inferomedial boundary, y = -37.547 + 20.319 × ln (age), for length of inferolateral boundary, y = -28.915 + 15.822 × ln (age) for transverse diameter, y = -69.790 + 38.73 × ln (age) for vertical diameter and y = -485.631 + 240.844 × ln (age) for projection surface area. Out of the 4 angles of the popliteal fossa the medial one was greatest, the inferior one the smallest, while the lateral one was somewhat smaller than the medial one and approximately 3 times greater than the superior one, with no difference with foetal age. In terms of morphometric parameters, the popliteal fossa in the human foetus displays neither male-female nor right-left differences. In the popliteal fossa, growth patterns of its 4 boundaries, vertical and transverse diameters, and projection surface area all follow natural logarithmic functions. All the morphometric data are considered age-specific reference intervals, which may be conducive in the diagnostics of congenital abnormalities in the human foetus.