The Anatomy And Histology Features Of Tracheal Carina And The Research Of Stent In The Region Of The Carina

Part 1 The morphological anatomy research of human tracheal carinaObjective To explore the anatomy and morphology features of human tracheal carina, including the distal trachea, carina of trachea and main bronchus in the right/left side.Methods Observations and measurements were made about the carina of trachea in 20 cadavers specimens (18 males,2 females).Standard tracheal and carina measurements included:outer transverse diameters and widths of posterior membrance in different part of trachea, lengths and inner diameters of the right and left main bronchus,subcarinal angels and so on. Differentiations and correlations about the these data were analysed statisticallyResults There are no statistical differentiations among the outer transverse diameters in different part of the trachea(in the upper, middle and distal trachea), but the differentiations are acquired about the widths of posterior membrance in different part of trachea. There is some correlation between the inner diameters of right main bronchus and the left side(R=0.605, P=0.005<0.05), and the former is relatively independent with some other factors (P>0.05).Conclusions①The shape of tracheal cartilage in the bifurcation of trachea is different from others, which is changed from C shape into the saddle, and it becomes the point of connection between trachea and the bronchus.②The concept of "region of the carina " is helpful to get better comprehension of the airway disease concerning carina.③The membrance of the posterior wall of the tracheal bifurcation is the widest point of the whole membranous wall,and it is probably the weakest part of the posterior wall of trachea.④According to the features of tracheal carina anatomy, Y-shaped airway stent is more fitful in this region.Part 2 Histology study of tracheal carina of Japanese white big-ear rabbitObjective Trachea and bronchus in histology consist of tracheal cartilages,membrance wall and the elastic fibers as the connections between two rings. However, there are still no definite views on the difference of different part of trachea and bronchus by now. In this research, similarities and differences in histology of trachea in white big-ear rabbit are studied in different part, statistic analysis are made to explore this question furthermore so that some theory basis may be provided for clinical prevention and treatment certain diseases in trachea and carina.Methods 30 Japanese white big-ear rabbits are randomly selected without considering the gender. The trachea and bronchus with the whole lung tissue are taken out after the rabbits were killed. Three parts as the tissue specimens in each rabbit are acquired respectively at three position:trachea tissue (1～2cm above the bifurcation), carina tissue, and bronchial tissue under the bifurcation, and they are marked as A,B,C.3 tissues are made into histological slides respectively in total of 90. Then the sections are observed and analyzed under the optical microscope with scale within its eyepiece(the scale is of no unit). The thickness of tracheal cartilage and smooth muscle in the posterior membranous wall and the amount of blood vessel in the ring of trachea/bronchus in each section are observed carefully and recorded as the raw data. Each section is measured 3 times and the average data is written as the final result. Statistic analysis is done to evaluate the differentiation and correlation in different position of the trachea.Results④The value of the thickness of tracheal cartilages is 3.00±0.78, 2.32±0.63,1.68±0.46 at the part A,B and C respectively. Differentiation is regarded as significant statistically by use of the analysis of variance(ANOVA, F=32.376, P=0.000<0.05).The mean value has the trend of A>B,B>C, that is, the cartilage in trachea above the carina is thicker than that of the carina, and the cartilage of the latter is thicker than the bronchial cartilage.②The value of the thickness of smooth muscle in the posterior membranous wall is 1.03±0.78,0.57±0.23,0.63±0.21 at the part A,B and C respectively. Analysis shows that the differentiation between A and B, A and C is significant(F=26.967, P=0.000<0.05), but the differentiation between B and C seems like insignificant(P=0.430>0.05). The mean value has the trend of A> OB, that is,the SM in trachea above the carina is thicker than that of the carina as well as the bronchial cartilage, and it seems that the area of carina is the weakest position of the whole SM in the airway.③The quantity of the blood vessel in the tracheal wall is 4.77±1.68,4.37±1.69 and 4.13±1.63 at the part A,B and C respectively, and there is no prominent differentiation (F=1.028, P=0.362>0.05).④There is no correlation between the thickness of CaL,SM,the quantity of BV in tracheal wall and the weight, body length and month of growing (P>0.05)Conclusions There is some differentiation of the airway histology at different position for Japanese white big-ear rabbit. The thickness of the CaL becomes thinner from the trachea above the carina to the bronchus, and the SM of membranous wall at the carina seems to be the most thinnest place of the whole airway. There is no difference for quantity of BV in tracheal wall at different position. There is no correlation between all three and the weight, body length, months of growing of rabbit.