Transverse ligament of the knee in human embryos aged 7 and 8 weeks.

The aim of the study was to trace the transverse ligament of the knee in staged human embryos. Investigations were carried out on 42 embryos of developmental stages 18-23 (44-56 postovulatory days) from the collection of the Department of Anatomy in Poznań. It was found that in embryos at stage 19 peripheral condensation of the mesenchymal interzone of knee joint, located anteriorly to the primordia of the cruciate ligaments, was recognizable. Clearly visible cellular primordium of the transverse ligament, connected with the medial and lateral menisci, was observed in stage 22. The primordium consisted of oval cells, arranged into densely packed parallel strands. The cells were greater than those forming the menisci. In embryos at stage 23 all intraarticular elements (articular surfaces, menisci and their ligaments, cruciate ligaments and transverse ligament) of the knee joint were clearly evident.