Newer concepts of anatomy of the lungs; advantages to surgeons,internists, bronchoscopist and radiologists

In the newer concept of the anatomical divisions of the lungs, the bronchopulmonary segment is the primary unit. Specific lung areas are identified by their relationship to the branch of the bronchus that serves them. The left upper lobe apical segment, for example, is that which is supplied by the left upper lobe apical bronchus. The boundaries of the segments are definitive; thin tissue surrounds each segment. Some diseases of the lungs tend to progress only "through channels"-reaching a segment via the specific airway serving it, and then frequently remaining within the segmental boundaries. The concept is of particular importance to surgeons because of the trend toward segmental resection and salvage of vital lung tissue. In addition, a more definitive nomenclature, useful to surgeons, internists, radiologists and bronchoscopists in designating the location of a lesion or a foreign body, is possible.     

NEWER CONCEPTS OF ANATOMY OF THE LUNGS—Advantages to Surgeons,Internists, Bronchoscopists and Radiologists

In the newer concept of the anatomical divisions of the lungs, the bronchopulmonary segment is the primary unit. Specific lung areas are identified by their relationship to the branch of the bronchus that serves them. The left upper lobe apical segment, for example, is that which is supplied by the left upper lobe apical bronchus. The boundaries of the segments are definitive; thin tissue surrounds each segment.Some diseases of the lungs tend to progress only “through channels”—reaching a segment via the specific airway serving it, and then frequently remaining within the segmental boundaries.The concept is of particular importance to surgeons because of the trend toward segmental resection and salvage of vital lung tissue. In addition, a more definitive nomenclature, useful to surgeons, internists, radiologists and bronchoscopists in designating the location of a lesion or a foreign body, is possible.     

The bronchial tree and lobular division of the chimpanzee lung

The bronchial ramification and lobular division in lungs of two chimpanzees (Pan troglodytes) were examined from the viewpoint of comparative anatomy, on the basis of the fundamental structure of bronchial ramification of the mammalian lung (Nakakuki, 1975, 1980). The right lung of the chimpanzee consists of the upper, middle, and lower lobes, whereas the left lung consists of the middle and lower lobes. The right and left lungs have the dorsal bronchiole system, lateral bronchiole system, and medial bronchiole system. The ventral bronchiole system is lacking on both sides. The right upper lobe is formed by the first branch of the dorsal bronchiole system. The right middle lobe is formed by the first branch of the lateral bronchiole system, and the right accessory lobe bronchiole is lacking. The remaining bronchioles constitute the right lower lobe. In the left lung, the upper and accessory lobes are lacking. The well developed middle lobe is formed by the first branch of the lateral bronchiole system. The left lower lobe is formed by the remaining bronchioles. Furthermore, these bronchioles are compared with those of the human lung byBoyden (1955).     

The bronchial tree and blood vessels of the Japanese monkey lung

The author injected various colored celluloid solutions into the bronchial tree and blood vessels of the lungs of five adult Japanese monkeys (Macaca fuscata) in order to prepare cast specimens. These specimens were investigated from the comparative anatomical viewpoint to determine whether the bronchial ramification theory of the mammalian lung (Nakakuki, 1975, 1980) can be applied to the Japanese monkey lung or not. The bronchioles are arranged stereotaxically like those of other mammalian lungs. The four bronchiole systems, dorsal, ventral, medial, and lateral, arise from both bronchi, respectively, although some bronchioles are lacking. In the right lung, the bronchioles form the upper, middle, accessory, and lower lobes, while in the left lung, the upper and accessory lobes are lacking and bi-lobed middle and lower lobes are formed. In the right lung, the upper lobe is formed by the first branch of the dorsal bronchiole system. The middle lobe is the first branch of the lateral bronchiole system. The accessory lobe is the first branch of the ventral bronchiole system. The lower lobe is formed by the remaining bronchioles of the four bronchiole systems. In the left lung, the middle lobe is formed by the first branch of the lateral bronchiole system. The lower lobe is formed by the remaining bronchioles. Thus, the bronchial ramification theory of the mammalian lung applied well to the Japanese monkey lung. The right pulmonary artery runs across the ventral side of the right upper lobe bronchiole. It then runs along the dorso-lateral side of the right bronchus between the dorsal bronchiole system and the lateral bronchiole system. On its way, it gives off branches of the pulmonary artery which run along the dorsal or lateral side of each bronchiole except in the ventral bronchiole system. In the ventral bronchiole system, the branches run along the ventral side of the bronchioles. The distributions of the pulmonary artery in the left lung are the same as those in the right lung. The pulmonary veins do not always run along the bronchioles. Most of them run on the medial or ventral side of the bronchioles. Some of them run between the pulmonary segments. In the right lung, these pulmonary veins finally form the right upper lobe vein, right middle lobe vein and the right lower lobe pulmonary venous trunk before entering the left atrium. However, the right accessory lobe vein runs on the dorsal side of the bronchiole and pours into the right lower lobe pulmonary venous trunk. In four cases out of the five examples, part of the right lower lobe veins pour into the right middle lobe vein, while the others enter the right lower lobe pulmonary venous trunk. In the left lung, the branches of the pulmonary veins finally form the left middle lobe vein and the left lower lobe pulmonary venous trunk.     

Airway Wall Area Derived from 3-Dimensional Computed Tomography Analysis Differs among Lung Lobes in Male Smokers

Background

It is time-consuming to obtain the square root of airway wall area of the hypothetical airway with an internal perimeter of 10 mm (√Aaw at Pi10), a comparable index of airway dimensions in chronic obstructive pulmonary disease (COPD), from all airways of the whole lungs using 3-dimensional computed tomography (CT) analysis. We hypothesized that √Aaw at Pi10 differs among the five lung lobes and √Aaw at Pi10 derived from one certain lung lobe has a high level of agreement with that derived from the whole lungs in smokers.

Methods

Pulmonary function tests and chest volumetric CTs were performed in 157 male smokers (102 COPD, 55 non-COPD). All visible bronchial segments from the 3^rd to 5^th generations were segmented and measured using commercially available 3-dimensional CT analysis software. √Aaw at Pi10 of each lung lobe was estimated from all measurable bronchial segments of that lobe.

Results

Using a mixed-effects model, √Aaw at Pi10 differed significantly among the five lung lobes (R² = 0.78, P<0.0001). The Bland-Altman plots show that √Aaw at Pi10 derived from the right or left upper lobe had a high level of agreement with that derived from the whole lungs, while √Aaw at Pi10 derived from the right or left lower lobe did not.

Conclusion

In male smokers, CT-derived airway wall area differs among the five lung lobes, and airway wall area derived from the right or left upper lobe is representative of the whole lungs.     

The bronchial tree and lobular division of the lung of the white handed gibbon

The bronchial tree and lobular division of the lungs of four white handed gibbons (Hylobates agilis) were examined from the viewpoint of comparative anatomy, based upon the fundamental structure of the bronchial ramifications of the mammalian lung (Nakakuki, 1975, 1980). The right lung of the white handed gibbon consists of the upper, middle, lower, and accessory lobes, whereas the left lung consists of the middle and lower lobes. Each lobe is separated by the interlobular fissure, on both sides. The right and left lungs have the dorsal bronchiole system, lateral bronchiole system, and ventral bronchiole system. The medial bronchiole system is lacking on both sides. In the right lung, the upper lobe is formed by the first branch of the dorsal bronchiole system. The middle lobe is formed by the first brach of the lateral bronchiole system, and the accessory lobe by the first branch of the ventral bronchiole system. The remaining bronchioles constitute the right lower lobe. In the left lung, the upper lobe bronchiole, which is the first branch of the dorsal bronchiole system, is lacking. Therefore, the middle lobe bronchiole, i.e. the first branch of the lateral bronchiole system, is well developed. The accessory lobe bronchiole, the first branch of the ventral bronchiole system, is also lacking. The remaining bronchioles constitute the left lower lobe. These features were compared with those of other apes and man.     

The bronchial tree,lobular division,and blood vessels of the lung of the silvered lutong (Presbytis cristata)

The lungs of three silvered lutongs (Presbytis cristata) were examined. The right and left lungs have the dorsal, lateral, ventral, and medial bronchiole systems, which arise from the corresponding sides of both bronchi, respectively. Bronchioles in the dorsal and lateral bronchiole systems are well developed, whereas those in the ventral and medial bronchiole systems are poorly developed and lack some portions. According to the fundamental structure of bronchial ramifications of the mammalian lung (Nakakuki, 1975, 1980), the right lung consists of the upper, middle, lower, and accessory lobes, whereas the left lung consists of a bilobed middle lobe and a lower lobe, in which the right upper lobe is extremely well developed. The right pulmonary artery runs across the ventral side of the right upper lobe bronchiole, and then across the dorsal side of the right middle lobe bronchiole. Initially it runs along the lateral side of the right bronchus and then gradually comes to run along the dorsal side. During its course, it gives off branches which run mainly along the dorsal or lateral side of the bronchiole. The left pulmonary artery runs across the dorsal side of the left middle lobe bronchiole, and then follows the same course as that in the right lower lobe. The pulmonary veins run medially or ventrally to the bronchioles, and finally enter the left atrium as four or five large veins.     

Size-dependent morphology of the conductive bronchial tree in four species of myomorph rodents

Size-dependent structural patterns in the conductive bronchial tree of four species of myomorph rodents of different body weight were determined by lung casts. The lungs of the harvest mouse, Micromys minutus, body weight 5–7 g, the house mouse, Mus musculus, body weight 35–45 g, the brown rat, Rattus norvegicus, body weight 200–400 g, and the African giant pouched rat, Cricetomys gambianus, body weight 1,200–1,800 g, were inflated to 20 cm H₂O, frozen, freeze-dried, hardened, and filled with silicone rubber. The casts were pruned, and branching pattern, diameter, and volume of the conductive bronchial tree were determined using a binocular magnifier. All four species have four lobes on the right lung and an undivided left lung, and the central bronchial tree on either side shows an identical monopodial branching pattern. Although the ramification of the central conductive bronchi is not size-dependent, the diameter and volume are. The diameter of the left main bronchus equals 1.24% of body length in Micromys and 0.6% in Cricetomys, and the conductive bronchial tree makes up 13% of the total lung volume in Micromys and 6% in Cricetomys. Relatively wider airways and a decline in airway resistance with declining body mass in small mammals compared to large ones result in a high ventilatory dead space, which is compensated for by a higher breathing frequency. © 1996 Wiley-Liss, Inc.     

Relative contribution of bronchial flow to subpleural region in dog lung.

The bronchial flow is approximately 1% of the total pulmonary flow. Anastomosis between the bronchial and pulmonary vessels occurs primarily at the microcirculatory level. It is assumed that bronchopulmonary anastomoses are present in a homogeneous manner throughout lung parenchyma. To investigate this issue, an in situ blood-perfused left lower lung lobe (500 ml/min) was prepared in a live dog. The bronchial flow rate in the entire lobe was monitored using the rate of volume gain in the reservoir while the pulmonary and bronchial flow in the subpleural region was monitored using laser-Doppler flowmetry. The results were expressed as ratio of bronchial to pulmonary flow rate for the entire lobe and for the subpleural region. We found that, for the entire lobe, bronchial flow was 1.0% of pulmonary flow, while for the subpleural region this ratio was much higher, with an average of 12%. In two different experimental conditions that were imposed to affect the global bronchial flow, these ratios changed in the same direction as the global bronchial flow. After transfusion of blood into the animal, bronchial flow increased to 1.7%, while the subpleural bronchial flow increased to 18% of the subpleural pulmonary flow. During elevation of venous pressure, bronchial flow decreased to 0.6%, while the subpleural bronchial flow decreased to 10% of the subpleural pulmonary flow. The differences in the ratios between the global and subpleural region may be explained by having low pulmonary blood flow in the periphery compared with the interior regions of the lung.(ABSTRACT TRUNCATED AT 250 WORDS)     

Branches of the left pulmonary artery supplying the basal segments of the lung

The studies were carried out on 100 left lungs taken from dead human bodies of both sexes whose age varied from 16 to 80 years. The pulmonary artery and the bronchus were injected with a 65% solution of duracryl and then digested in sulfuric acid. The specimens obtained were then examined to determine the number and dimensions of the branches of the basal portion of the left pulmonary artery penetrating into the basal segments of the left lower pulmonary lobe. Their length was 60 mm at the most, and their diameter 9.8 mm. Three types of ramification of the basal portion of the left pulmonary artery were distinguished on the basis of the trunks, segmental and subsegmental branches present. In 70% of the cases the branches penetrating into the basal segments showed tree-like type, in 3% of the cases showed bushy-like type, and in 27% of the cases middle type.     

The lobular division,bronchial tree and blood vessels of the squirrel monkey lung

The lobular division, bronchial tree, and blood vessels in lungs of seven squirrel monkeys (Saimiri sciureus) were examined from the viewpoint of comparative anatomy. The right lung of the squirrel monkey consists of the upper, middle, lower, and accessory lobes, whereas the left lung consists of the upper, middle, and lower lobes. These lobes are completely separated by interlobular fissures. In three of seven examples examined the left middle lobe was lacking. The squirrel monkey lung has four bronchiole systems, i.e. dorsal, lateral, ventral, and medial, on both sides. The upper lobes are formed by the first branches of the dorsal bronchiole systems. The middle lobes are formed by the first branches of the lateral bronchiole systems. The remaining bronchioles constitute the lower lobes. In addition to the above lobes, in the right lung, the accessory lobe is present, being formed by the first branch of the ventral bronchiole system. The right pulmonary artery runs across the ventral side of the right upper lobe bronchiole, and then across the dorsal side of the right middle lobe bronchiole. Thereafter, it runs between the dorsal bronchiole and lateral bronchiole systems along the dorso-lateral side of the right bronchus. During its course, the right pulmonary artery gives off the arterial branches which run along each bronchiole. These branches run mainly along the dorsal or lateral side of the bronchioles. In the left lung, the pulmonary artery and its branches run the same course as in the right lung. The pulmonary veins run mainly the ventral or medial side of the bronchioles, and between the bronchioles.     

The bronchial tree and lobular division of the gorilla lung

The bronchial ramification in one specimen of gorilla lung was examined from the viewpoint of comparative anatomy, on the basis of the fundamental structure of bronchial ramification in the mammalian lung (Nakakuki, 1975, 1980). The right lung of the gorilla consists of the upper, middle, lower, and accessory lobes. The right lung has the dorsal, lateral, and ventral bronchiole systems, but the medial bronchiole system is lacking. The upper lobe is formed by the first branch of the dorsal bronchiole system. The middle lobe is formed by the first branch of the lateral bronchiole system. The accessory lobe is formed by the first branch of the ventral bronchiole system. The remaining bronchioles constitute the lower lobe. The left lung consists of the middle and lower lobes; the upper and accessory lobes are lacking. The left lung has the dorsal and lateral bronchiole systems, but the ventral and medial bronchiole systems are lacking. The middle lobe is formed by the first branch of the lateral bronchiole system. The remaining bronchioles constitute the lower lobe. The bronchial ramifications of the gorilla lung are rather similar to those of the human lung.     

Branches of the left pulmonary artery vascularizing the left upper pulmonary lobe

The studies were carried out on 100 left lungs taken from dead human bodies of both sexes whose age varied from 16 to 80 years. The pulmonary artery and the bronchus were injected with a 65% solution of duracryl and then digested in sulfuric acid. The specimens obtained were examined to determine the number and dimensions of the branches of the left pulmonary artery penetrating into the upper lobe of the left lung as well as the places at which they branch off from this artery. It was found that in most cases 4 branches ramified from the left pulmonary artery. Their length was 30 mm at the most, and their diameter, 12 mm. In about 50% of the cases the branches which penetrated into the lobe were the apicoanterior trunk, the lingular branch and 1 or 2 subsegmental branches, in about 25% of the cases almost all segmental branches penetrated into the lobe separately. In about 20% of the cases the apicoposterior trunk and independent segmental or subsegmental branches were present. Only in about 5% of the cases did the branches under consideration include the apicoposteroanterior trunk and the remaining segmental and subsegmental branches.     

Leakage of macromolecules in ventilated and unventilated segments of preterm lamb lungs.

The movement of macromolecules into and out of unventilated lung segments was evaluated in prematurely delivered and ventilated lambs. Seven lambs at 130 days gestational age had a bronchial balloon placed at birth before the first breath to obstruct the left lower lobe. Surfactant and 131I-albumin were instilled into the left lower lobe while surfactant and 125I-albumin were instilled into the remaining lung, and 70,000 molecular weight [3H]dextran was given into the vascular space at birth. Twenty-five percent of the lung by weight was not ventilated, and 24% of the total leak of dextran from the vascular space was recovered in the unventilated lungs at 3 h. An epithelial leak of protein from the two lung regions was documented by the loss of 11.4 and 18.4% of the labeled albumins in the nonventilated and ventilated lung regions, the appearance of 4.9 and 7.5% of the airway-instilled albumin in the vascular space from the nonventilated and ventilated lung regions, and the recovery of the labeled albumins in the carcasses of the lambs. The bidirectional flux of macromolecules was larger in the ventilated than in the nonventilated lung regions, indicating that ventilation can increase the leak of protein in the preterm lung. The lung areas that were never exposed to ventilation or oxygen also demonstrated a large bidirectional flux of macromolecules, a finding not present in the fetus, fullterm newborn, or adult. These findings indicate that ventilation is not solely responsible for the increased protein leak found in preterm lungs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Why are there so many threat displays?

The morphology of branching trees in general, and of the bronchial tree in particular, can be described in terms of three parameters, the diameter, length and branching ratios. These are the factors by which mean diameter and mean length increase in successive orders towards the trachea, and by which the number of branches increases in successive orders away from the trachea. Orders of branching are counted from the periphery towards the trachea, according to the method of Strahler. A model of from two to nine orders, and of constant total length and volume, was used to investigate the effect of varying the above parameters on the calculated pressure difference across the model during flow. In particular, the branching ratio was set at known values for dog and human lungs, and diameter and length ratios were independently varied. Known data from dog and human lungs were found to be close to the points predicted by the model where the lines of minimal resistance and minimal entropy production crossed. Other factors which may affect the values of these parameters are discussed.     

猕猴肝门静脉系统和肝静脉系统的观察

以铸型方法及实体解剖观察了猕猴(Macaca mulatta) 肝的门静脉分支和肝静脉分支。猕猴肝门静脉与人、猪、兔、牛、羊等相似, 同样可将全肝分成二叶四段, 即左叶、右叶; 左外侧段、左内侧段、右内侧段、右外侧段。尾状叶的左、右部可分别隶属于左叶和右叶。猕猴肝大静脉有左外侧叶肝静脉、左内侧叶肝静脉、肝中静脉、肝右静脉及尾状叶肝静脉。此外, 作者对哺乳动物门静脉分支的规律性, 猕猴肝大静脉的命名及吻合作了讨论。     

Increased resistance in postobstructive pulmonary vasculopathy: structure-function relationships

Postobstructive pulmonary vasculopathy (POPV) was produced by chronic ligation (120 days) of the left main pulmonary artery of seven dogs. To explain the abnormal physiological changes found using arterial and venous occlusion (AVO) in POPV (J. Appl. Physiol. 69: 1022-1032, 1990), the light-microscopic morphology, morphometry (n = 5), and ultrastructure (n = 6) of ligated left lower lobes were compared with contralateral control right lower lobes. First, there was a proliferation of bronchial vessels around pulmonary vessels and airways to explain bronchial blood flow rates of 330 ml/min in left lower lobes. The walls of the bronchial vessels contained smooth muscle with minimal elastic tissue and prominent myoendothelial junctions. Second, focal bronchopulmonary anastomoses were seen in pulmonary arteries approximately equal to 100 microns diam, which is consistent with our conclusion that the major site of communication is at the precapillary level and suggests that the limit between arterial and middle segments defined by AVO may lie in arteries of approximately equal to 100 microns. Third, to explain the increased arterial resistance in POPV, the pulmonary arteries had an increased percent medial muscle thickness, peripheral muscularization, and focal intimal thickening but had no plexiform lesions. The ultrastructure of the arteries revealed new intimal cells and numerous myoendothelial junctions rarely found in controls. Capillaries and veins were only subtly altered. Fourth, the hyperreactivity of arteries to serotonin and of veins to histamine found using AVO was partially explained by the increased medial thickness and decreased diameter but may also be due to increased receptor concentration or related to the myoendothelial junctions. We conclude that most of the hemodynamic alterations in POPV are related to morphological abnormalities and that this model has clinical and experimental relevance in the study of bronchopulmonary vascular interactions.     

Peculiarities of human lung prenatal morphogenesis at the first trimester of pregnancy in different periods after Chernobyl accident

The comparative histological and morphometric analysis of the bronchial structures of human fetal lungs was performed. Fetal lungs were taken from pregnant women living in radionuclide polluted zones (Novozibcov, Bryansk region) or in control regions (Moscow) in different periods after Chernobyl accident. Relative areas of the bronchial epithelial tubes and mesenchyme, quantity of bronchial branches and buds (end sections) of epithelial tubes on cut area unit were determined. The dates received in 1992-1993 showed the delay of fetal bronchial growth and branching in comparison with control. It can be estimated as tissue dysplasia of lungs from fetuses of mothers living in Novozibcov. The material received in 1995 showed the more intensive growth of bronchial branches in human fetal lungs than the material from Novozibcov and of the Moscow control, taken in 1992-1993. These date suggest the heterogenous character of lung prenatal morphogenesis reactions of offspring from pregnant women lived in different periods on controllable territories of Bryansk region.     

Distribution of the pulmonary artery and vein in the lung of the white handed gibbon

The lungs of four white handed gibbons (Hylobates agilis) were examined. The right pulmonary artery runs across the ventral side of the right upper lobe bronchiole, and then traverses the dorsal side of the right middle lobe bronchiole. Thereafter, it runs along the dorso-lateral side of the right bronchus, between the dorsal bronchiole system and the lateral bronchiole system, and gradually follows the dorsal side of the right bronchus. During its course, it gives off arterial branches which run along each bronchiole. The left pulmonary artery runs across the dorsal side of the left middle lobe bronchiole and then along the left bronchus as in the right lung. The branches of the pulmonary artery run mainly along the dorsal or lateral side of the bronchiole, while the pulmonary veins run mainly the medial side of the bronchioles or between them. However, in a few portions, the pulmonary veins run the lateral side of the bronchioles. Finally, they enter the left atrium with four large veins i.e. the common trunk of the right upper lobe vein and right middle lobe vein, right lower lobe pulmonary venous trunk, left middle lobe vein, and left lower lobe pulmonary venous trunk.     

Reversibility of complete unperfusion in a patient with recurrent hemoptysis

We present a case of a 68-year-old woman with a history of mild smoking and chronic bronchitis who showed recurrent hemoptysis. She presented with a nearly normal chest roentgenogram, a non-diagnostic fiberoptic bronchoscopy and a computed tomography and lung scanning both of which were highly suggestive for malignancy. In fact, the former showed obstruction of the main left bronchus, of the superior bronchus for the left upper lobe and of the apical bronchus for the left lower lobe, the latter showed a total cessation of blood flow through the left lung. Pulmonary angiography, however, was normal and aortography showed dilatated and twisted left bronchial arteries. Computed tomography and lung scanning came back to normal after bronchoscopic aspiration of endobronchial clots and a nonspecific antibiotic therapy were carried out. Although very infrequent, bronchial stenosis on CT and complete monolateral unperfusion on lung scintigraphy may occur in patients with hemoptysis of benign origin. We recommend the use of pulmonary arteriography in patients with the above pattern when diagnostic doubt remains after bronchoscopy.