Applied Anatomy Of The Lumbosacral Trunk And Its Surrounding Structures

Purpose: To provide anatomy data for the diagnosis and treatment of the injured lumbosacral trunk and for the operation technique of its adjacent areas. Methods: By observing the lumbosacral trunks of 31 adult bodies (33 examples), the distributions and runs of the blood vessels and the nerves around them, and by measuring anatomically the data significant to the clinic. Results: 1.there 're great variations in the lumbosacral trunk itself, so do its presence and absence, length, linea aspera fermoris, runs and compositions. The start-stop point of the nerve preramus L5 in the specimen without forming the lumbosacral trunk is relatively constant and its runs and most adjacent relations are similar to the lumbosacral trunk.2. The most vunable part of the lumbosacral trunk lies in the upper fringe of the alae sacri.3.The lumbosacral truks are mostly located in the inter fringe of the musculus psoas major and the rear of the iliac blood vessels, so exploration can be made between them. The left lumbosacral trunk is near to the small iliac artery and attention should be focused on the identification and treatment of it while exploring. 4. The nerve preramus L4 , the femoral nerve, the obturator nerve and the communicating branch are liable to injury in the front of the ligamentum iliolumbale. Exploration can be made along the external side of the upper fringe of the crista iliaca before passing the rear of the musculus psoas major, it can also be made through the side of lumber 5 vertebra and the internal side of the musculus psoas major. 5. Musculi 4 intertransversarii is far from the initiation part of the nerve preramus L5 and there isno great possibility to create damage to it after the fracture, the venerable parts are the nerve preramus L4, the femoral nerve , the obturator nerve and the communicating branch under it. Conclusions: 1. The variations in the lumbosacral trunk itself are great , the start-stop point of the nerve preramus L5 in the specimen without forming the typical lumbosacral trunk is relatively constant and its runs and most adjacent relations are similar to the lumbosacral trunk, so exploring the lumbosacral trunk without knowing its variations should be subject to the anatomy of the lumber 5 nerve preramus. 2. The lumbosacral trunk, the femoral nerve and the obturator nerve all have their vulnerable parts, so priority should be given to them while exploring.