Topography of the femoral nerve in relation to components of the iliopsoas muscle in human fetuses.

Studies were performed on 60 human fetuses of both sexes of 35 to 365 mm C.-R. length (9-40 weeks). The psoas minor muscle was found in 25.8% of cases independently of sex and body side. In 6.45% of cases the muscle continued into psoas major muscle by short, weakly developed tendon. In 97.5% of studied fetuses junctions between tendons of psoas major and iliacus muscles was observed. In 2.5% of cases an independent, short tendon was found in the half of length of the iliacus muscle. In 7.5% of cases connection between the psoas major and iliacus muscles was found. In all cases femoral nerve originated from the lumbar plexus between two layers of the psoas major muscle and it ran in the groove between the psoas major and iliacus muscles towards the muscular lacuna. In 5.0% of cases the nerve divided into crura. In 2.5% of cases the crura embraced anteriorly and posteriorly bundles of the psoas major muscle as well as in 2.5% of cases bundles of the iliacus muscle.