Documents

5 pages
195 views

A Study on Anatomical Dimensions of Bronchial Tree

of 5
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Share
Description
anatomy
Transcript
    International Journal of Research in Medical Sciences | July 2016 | Vol 4 | Issue 7 Page 2761 International Journal of Research in Medical Sciences Shaik Z et al. Int J Res Med Sci. 2016 Jul;4(7):2761-2765 www.msjonline.org  pISSN 2320-6071 | eISSN 2320-6012 Research Article A study on anatomical dimensions of bronchial tree Zareena Shaik*, Venkata Ramulu M., Hanimann K. S. INTRODUCTION In the light of increase in incidence of pulmonary diseases, there is a concomitant increase in study of lungs and bronchial tree morphological and clinically. The exchange of respiratory gases is the basic essentiality of life process in all the living organisms. This system has greatly evolved from unicellular to mammalian airway passage. In the late years Diemerbroack identified the bronchial tree pattern. 1,2  The study of this bronchial tree and their dimensions is useful in various aspects as to know any abnormalities of airways like pneumonia,  bronchial obstructions, foreign bodies, mediastinal masses, to maintain posture for patients suffering from suppurative lung disorders; for anesthetist to know the caliber of trachea for intubation, bronchoscopy. Bronchial anatomy is essential knowledge for thoracic surgeons in various surgical maneuvers. Bronchoscopy  procedures are widely used in diagnostic and therapeutic  purposes. Bronchial pattern of pulmonary diseases is characterized  by alterations in bronchial wall thickness and lumen diameters. To study the normal morphology of divisions of bronchial tree quantitatively and qualitatively, to know the anatomical dimensions of principal bronchi, to note the morphological variations, to note angle of carina. The ABSTRACT Background:  The principle of minimal work requires that the conducting airways of human lungs should have a maximum radius for minimal resistance to gas flow. Malphigi et al said that the trachea terminated in dilated vesicle. The study of bronchial tree and their dimensions is useful in various aspects as to know the entry of foreign particles, to maintain posture for patients suffering from suppurative lung disorders. For anaesthetist to know the caliber of trachea for intubation, bronchoscopy. Bronchial anatomy is essential knowledge for thoracic surgeons in various surgical maneuvers. Methods:  The study of bronchial tree is done in 20 pairs of lungs and the following are observed. Various dimensions like tracheal length, width, sub carinal angle, Length and diameter of principal bronchi from the level of bifurcation of trachea is noted with digital Vernier calipers and scale. Results:  Though dimensional analysis of bronchi was studied, it shows no significance from earlier studies. In the  present study all the dimensions are within normal limits. Out of 20 pairs 6 specimens showed variations in the  branching patterns. Conclusions:  The results suggests that there are limited variations in the dimensional study, now a days  bronchoscopy procedures are widely used in diagnostic and therapeutic purposes. The sub carinal angle indirectly helps in diagnosis of cardiovascular problems and for surgical resection of segments Keywords: Trachea, Angle, Bronchial tree, Branching pattern Department of Anatomy, Viswabharathi Medical College, Kurnool, Andhra Pradesh, India Received:  09 May 2016 Revised:  16 May 2016 Accepted: 03 June 2016 *Correspondence: Dr. Zareena Shaik, E-mail: zareenasmc@gmail.com Copyright:  © the author(s), publisher and licensee Medip Academy. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the srcinal work is properly cited. DOI: http://dx.doi.org/10.18203/2320-6012.ijrms20161946  Shaik Z et al. Int J Res Med Sci. 2016 Jul;4(7):2761-2765 International Journal of Research in Medical Sciences | July 2016 | Vol 4 | Issue 7 Page 2762 knowledge of this study is of immense value in endoscopic procedures for diagnostic and therapeutic  purposes. The principal bronchus plays a major role in transmitting air to and from the lungs. The sub carinal angle indirectly helps in diagnosis of cardiovascular  problems and for surgical resection of segments or lobes in diseases of lungs. The principle of minimal work requires that the conducting airways of human lungs should have a maximum radius for minimal resistance to gas flow. The dimensions of branched structures such as airways  bronchial tree is important factor in determining the efficiency of physiological process. The carina located about 25cm from the incisor teeth and 30cm from the external nares. It lies at the level of T5 vertebrae at expiration and T6 in inspiration. The proximity of the carina to the vertebral column widens the bifurcation angle; measurement of carina  position in relation to tracheal midline. This data may be useful for calculating dead space. The Bronchial tree is aptly name for its resemblance to the branches of a tree, as larger tubes perpetually concede to smaller tube in an intricate framework of branches. Right around the level of sternal angle, just posterior to manubrium. The trachea splits off into the right and left  principal bronchi surrounding the lumen of each extending principal bronchi, rings of cartilage keep the larger airways open as they branch off into smaller tubes. The right primary branch lies at a more upright angle, which increases the chances of foreign particles slipping through the tubular formation. Each principal bronchi is then segregated off once again as it descends into the lungs, forming lobar and then segmental bronchi also known as secondary and tertiary bronchi. Usually the  bronchial segment of interest will be the left, as the length is twice that of right. The larger diameter of bronchi optimizes gas flow during ventilation. The right bronchi lies more upright angle so increase in more chance of foreign particle slipping into it. The study of bronchial tree is done by both invasive and non-invasive techniques like bronchoscopy, computed tomography scan, magnetic resonance imaging scan. In the present study 20 pairs of lungs are taken and dissected out till the level of terminal bronchi and various  parameters are calculated. METHODS A gross anatomical dissection of embalmed cadavers was conducted from the department of anatomy, Viswabharathi medical college, Kurnool, Andhra Pradesh, India. Instruments used are forceps, scalpel, and rectangular trays, wooden blocks, measuring tape, Digital calipers, measuring scale are used in the present study. An incision was done on either side of sternum, ribs, clavicle were cut with the bone cutter, sternopericardial ligaments were ligated and cut, pericardium is incised to view the pulmonary vessels entering the lung are cut, and separated. The trachea is cut at the lower end of the cricoid cartilage and separated from oesophagus  posteriorly. The lungs are removed enmass from the thoracic cavity and washed thoroughly with water, soaked in 10% HCl. Later the parenchymal tissue is scraped with the scalpel and blunt forceps. The bronchial tree is cleaned up to the third generation, dried in air and kept on paper for outline the margins. The study of measurements as follows: 1-Tracheal length, 2-width of trachea, 3-subcarinal angle, 4-length of right bronchus, 5-length of left bronchus, 6-angle formed between right and left principal bronchus.  Figure1: Measurements of the study. RESULTS Tracheal length: It is ranging between 5.8cm and 9.2cm and on average was 7.8cm, Tracheal diameter- on average was 1.47cm and ranging from 1.0cm to 2.4cm, number of tracheal rings-these are c-shaped hyaline rings ranged between 10 and 18 on average 12 rings. Table 1: Dimensions of trachea. Tracheal length   Tracheal diameter  In adults 7.4-9.2cm 12mm-20mm In fetuses 3.0-4.6cm 2mm-4mm Average range of tracheal length - 7.87cm, Tracheal diameter-16mm, The incidence of different shapes at the upper end of trachea was studied and analyzed in fetuses  based on crown-rump length, the length and diameter of trachea steadily increasing in fetus. The average mean length of right main bronchus from the level of bifurcation is right bronchus length 2.0-2.2cm, Left bronchus length 3.8-4.6cm. The average mean diameter of right main bronchus is 14mm-18mm and left is 11mm-13mm. The relationship of diameters of both right and left main bronchi of males  Shaik Z et al. Int J Res Med Sci. 2016 Jul;4(7):2761-2765 International Journal of Research in Medical Sciences | July 2016 | Vol 4 | Issue 7 Page 2763 and females was correlated in a linear fashion but not  precise enough to be clinically evaluated.  Sub carinal angle The angle between two principal bronchi varied between 40degrees and 78 degrees. The mean angle is 53.45 degrees.  Variations in branching pattern Right lung- In 2 specimens the upper lobar bronchus took srcin at the level of carina. In 2 specimens the middle lobar bronchus srcinated from antero medial surface of main bronchus and ran downwards medially instead of  being lateral in direction. Left lung-In 1 specimen the upper lobar bronchus divided into apical and antero- posterior segmental bronchi. Table 2: Dimensions of principal bronchi. Right bronchus Number of specimens Left bronchus Number of specimens Length Diameter Length Diameter 1.6-2.0cm 10-12mm 6 2.6-3.0cm 9-10mm 5 2.0-2.2cm 12-14mm 4 3.0-3.6cm 10-12mm 7 2.2-2.4cm 14-16mm 8 3.6-4.0cm 12-14mm 4 2.4-2.6cm 16-18mm 2 4.0-4.5cm 14-16mm 4 Table 3: Dimensions of bronchial tree. Trachea Sub carinal angle Right main bronchus Left main bronchus Length Width No. of. rings Range 5.8-9.2 1-2.4 10-18 40-70 1.6-2.6 2.6-4.6 Average 7.87 1.6 12 53 degrees 2.0-2.2 3.8-4.6 Figure 2: Radiographic view and bronchoscopic view of angle of carina. Figure 3: Measuring with Vernier calipers. Figure 4: Dissection of bronchial tree. DISCUSSION The occurrence of variations in the length and diameters of main bronchi is fairly common and there are not many variants. The present aimed, In order to find an objective method for measuring narrowing of small airways. The lengths and diameters have a lot of endoscopic importance and studied by many authors (Hannallah, Romanes GJ, Sahni D, Harjeet, Gray H, Hampton T, Horsefield K, Cumming H et al). 3-8  According to Gray H the average length of right main  bronchus -2.2cm and that of left -5cm. 6  The present study supports the above statement as the average  Shaik Z et al. Int J Res Med Sci. 2016 Jul;4(7):2761-2765 International Journal of Research in Medical Sciences | July 2016 | Vol 4 | Issue 7 Page 2764 length was as more than ½ of specimens fall under this range. The review of literature revealed measurements of  bronchial tree done by dissection of specimens, chest X-rays, CT-scan. In the present study various parameters are measured and compared with literature. Murray et al reported that the tracheal bifurcation angle refers to the  both inter bronchial and sub carinal angles. 9  Normal ranges between 40 degrees to 70 degrees with a mean value of 60-65 degrees.  Sub carinal angle  Latarjet M studied CT scans of 129 cases and found the angle71 degree and the range between 40-108 degrees. 10  Coppole V examined CT scans of 500 patients and found the angle as 79.7 degrees and varied between 37-105 degrees. 11  The present study shows the angle 53.4degrees and the range is between 40-70 degrees. Figure 5: Study of subcarinal angle by authors. Tracheal Diameter Breatnach   studied x rays of 808 patients and found the diameter to be 2.5-2.7 cm in males and 2.1-2.3 in females. 12  Sternberg S in his text book of diagnostic surgical pathology described as the tracheal diameter as 2-2.5cm. 13  The present studies shows the diameter as 1.69cm on average and varied between 1.2 and 2.5cm. Table 4: Dimensions of trachea in adults. Name of author   Average length   Average diameter  Standring S et al 10-11cm 12mm Romanes GJ et al 10-12cm 11mm Sinnatamby et al 10cm 20mm Datta AK et al 10-11cm 12mm Present study 7.8-9.6cm 16mm Tracheal length Sternberg S in his textbook of diagnostic surgical  pathology 3 rd  edition described the tracheal length to be 11 cm long. 13  Rosen FS studied 50 specimens al  pathology 3 rd  edition described the tracheal diameter as 2.0- 2.5 cm. 14  A CT scan study by leader JK studied in 43specimens and found length to be 7.0-8.9cm. 19  The  present study shows the length on average 7.8-9.6cm. Number of tracheal rings Michael G   told that for every 2 cm there are 2 rings. 15  Rosen FS studied 50 specimens and observed that trachea on average contains 13.3 rings. 14  In the present study there are 14 rings. Right main bronchus   Length-  Snell   RS et al in text book of clinical anatomy 7 th  edition describes the length as 2.5 cm. 16  Present studies show the length to be 2.28 cm on average.  Angle - Miller studied by gross dissection and found the angle as 20 degrees. 17  Boyd E studied 100 cases and found the angle between 27-30 degrees. 18  In the present study the angle is 43.4 degrees on average. Table 5: Dimensions of principal bronchi. Previous studies Present study Mean length RMB-2.2cm Mean length LMB-5cm Mean length RMB-2.0cm Mean length LMB-4.2cm Mean diameter RMB -13 to 15mm Mean diameter LMB-11 to 13mm Mean diameter RMB-11 to 12mm Mean diameter LMB-11 to 13mm Many attempts of variations in the diameters of main  bronchi given in the range of RMB-13 to 15mm and that of LMB-11 TO 13mm. Left main bronchus  Length - Richard S Snell in text book of clinical anatomy 7 th  edition describes the length as 4.5 cm. 16  Present studies show the length to be 3.86 cm on average.    Angle  –  Miller studied by gross dissection and found the angle as 40 degrees. 17  Boyd E studied 100 cases and found the angle between 43.5  –   46 degrees. 18  In the  present study the angle is 39.68 degrees on average. CONCLUSION Prior knowledge of possible anatomical variants may help the surgeons to reduce the risk of accidental damage for cardiothoracic surgeons, ENT specialists, and anaesthetists; increasing opportunities to enlighten radiological importance with CT. Scan, X-rays, systematic identification of endobronchial anatomy during bronchoscopy procedures. The present study was done in 20 pairs of lungs and observed .The diameters and lengths are determined in a linear fashion in present study. The tracheal bifurcation angle has a wide range in normal subjects and the absolute measurement of the carina angle is of little diagnostic value.
Related Documents
View more...
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks
SAVE OUR EARTH

We need your sign to support Project to invent "SMART AND CONTROLLABLE REFLECTIVE BALLOONS" to cover the Sun and Save Our Earth.

More details...

Sign Now!

We are very appreciated for your Prompt Action!

x