Structure of infrapatellar synovial ligament in dogs

The knee joint of the dog is frequently the subject of surgery if the cruciate ligaments or the menisci are injured. In the knee joint of the dog we find a ligament, which is spread out between the anterior part of the fossa intercondylaris ossis femoris and the corpus adiposus infrapatellaris. This ligamentum synoviale infrapatellare has not previously been described and represents a homologous structure to the plica synovialis infrapatellaris of human knee joint. Just like the latter and just like the cruciate ligaments it is a rudiment of a septum articulare genu, which is spread out between an articulatio femorotibialis and an articulatio femorofibularis in the early phylogenesis of tetrapods. The ligamentum synoviale infrapatellare of the dog consists of a stratum synoviale and a stratum spinosum, which includes blood vessels, nerves, many collagenous fibres and some elastic fibres. We do not find evidence for sensory nerve endings or corpuscular receptors. Therefore a servering of the ligament during knee joint surgery does not affect the proprioceptive potential of the knee joint.