A Study On The General Anatomy Of Lumar Plexus Of SD Rats And Its Innervation On Lower Limb Muscles By Means Of EMG

With the development of modern industry and transportation, the morbidity of sacral fracture combined with sacral plexus avulsion continue to increase year by year. The rate of the sacral nerve injury caused by sacral fracture can be as high as between22percent and60percent,which is far more than that in times of sacral injury accompanied by pelvis fracture.Due to the improved internal fixation techniques, most of the sacral fractures can be properly reduced and sufficiently fixed,the deformed healing can be very scarce; However, sacral nerve injury may pose a great challenge to orthopeadics surgeon and it has become a major health hazard to the patients. Its clinical symptoms can be characterized by limp, steppage, sense disturbance of the affected position such as crus posteria lateral skin, leg posterial skin, dorsal lateral skin, planta pedis skin, the atrophy of gluteus maximus,gluteus medius,musculus gastrocnemius, knee flextion inability.some patients can suffer from partial bladder dysfunction,sex function disorders.Early nueral decompression techniques should be applied to the entrapped nerves. However, in the event of dennis Ⅲ sacral fracture accompanied by nerve injury, it is necessary to decompress the sacral canal,sacral foramina.In spite of this, all the measures such as conservative measures, internal fixation techniques,nerve decompression have no effect on nerve root avulsions and it remains an intricate problem to be settled.So it is worthwhile to explore the feasibility of autologous nerve graft for nerve restoration. As the number of costal nerve fibres is normally as many as10,000and30,000, most of which are sensory nerves instead of mortor nerves,the number diference is so great,it is not unreasonable to displace the costal nerve to repair lumbarsacral nerve root or cauda equina nerve. Anatomically, it is worth exploring the possiblity of repair the affected lumbarosacral plexus by means of normal nerves. This experiment is aimed to analyze the weight ratio of the innervation of lumbar by virtue of electrophyiology, which might help to find the ideal nerve power source for the repair of the injured sacral plexus.PART ONEObjective:observe the general anatomy of the rats and facilitate the EMG detecion and record with the aquired anatomical knowlege of a rat,Methods:15rats has been prepared for the experiment.With10percent methyl aldehyde irrigated into a rat’s heart, it is easier to observe the gross anatomy of its lumbar plexus.Results:There are six pairs of lumbar plexus together. While sciatic nerve consists of L5,L6,femoral nerve is made up of L2,L3,L4,which innervate quadriceps femoris. At the site of spine of T12,13, the1/3cephal part of L1, L2, lumbal cord originates from. Its anterior root is small, but its posterior roots are relatively bigger.Conclusions:the anatomical lumbar structure is different from human being.There are only5pairs lumbar nerve root in human being.However, rats boast of an extra pair L6. PART TWOObjective:select some power nerve source to repair the injured sacral plexus by means of the EMG. Of course, such lumbar nerve should have least influence on the movement of lower limber.Methods:select20adult rats regardless of its sexes weighed from250-300g.Expose lumar plexus and record the multiple action potienal of lumbar muscles. After analyzing the recorded data with one-factor analysis of variance.Results:stimulate L2nerve root,the maximum wave alpitude average less than lmv(p<0.05). After stimulating L3nerve root, we record the evident action potiential of quadriceps femoris,which is higher than other groups (p<0.01).With the stimulus of L4, four groups of muscle recorded higher action potiential than other groups and its average value is bigger than1mv. When it comes to L5and L6, the results are similar with recorded action potiental at gastrocnemial muscle than other groups.Conlusions:By means of EMG, L2shows less motion control of SD rat’s lower muscles.So we can consider the feasibility of use L2as power nerve source to repair the injured sciatic plexus.