树鼩(Tupaia belangeri chinensis)的脊神经丛

THE SPINAL PLEXUS OF TREE SHREW (Tupaia belangeri chinensis)

由于树鼩在系统发育方面所具的特殊性,以及当今实验动物的小型化趋向,树鼩正在被开发成为新型的实验动物,其生物学特性的研究随之蓬勃开展,如对染色体(陈宜峰等,1981)、神经生理(刘世熠等,1982)、血象(邹如金等,1983)、骨髓象(张耀平等,1986)、血液生化(彭燕章等,1986;陈保生等,1983)、皮纹(Haines,1955;张耀平等,1984)、解剖(Le Gros Clark,1924、1926;George,1977)、

With regard to the specific taxonomic position and the suitability for experiments with its small body, tree shrew has become a new intriguing experim-etnal animal, researches of become a new intriguing experimetnal animal, researches of biological characteristics of which is being developed very quickly as well. The resutls obtained from 20 examples for cervical plexus, brachialand and lumbosacral plexus respectively are as following. 1. The cervical plexus is composed of C2-4 constantly, but some differences could be seen among nerves making up their compositions. 2. There is not the real ansae hypoglossi, the nerves innervating the m. omohyoideus, m. thyrohyoideus and m. sternothyroideus come from or via r. descendens hypoglossi of C1 (see Fig. 1 and 2). 3. The compositions of the phreni nerve variatc greatly, they come from C3 to C7, but C4 and C5 are the constant condition. The ration for the resources of nervous root are 15% in the C3, 100% in the C4, 100% in the C5, 4% in the C6 and 5% in the C7. 4. The permanent elements in the brachial plexus consist of C5-T7, which combine into the upper, middile and lower trunks, lateral cord, medial cord and posterior cord, while the later forms two nervous ansae which is similar with that in the Cercopithecidae (see Fig. 3). In both the composition of plexus and the resource of roots, brachial plexus is the most permanent one in the three nervous plexus. 5. There exist some variations in n. suprascapularis, which is composed of C5,6 (70%) or C6,6,7, (30%). 6. Lumbosacral plexus consist from L1 to S2 (65%) or from L2 to S2 (35%) (sec Fig. 4 and 5). 7. Some changes ann be found in the resources of nervous root, which may have not any permanent one among the lumbosaeral plexus.