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J. UOEH, 2(4): 463-468 (1980) 463

(Original)

Corrosion Anatomy of the Eparterial Bronchi in the Rough

Toothed Porpoise, Steno bredanensis

Teruyuki HoJo

DePartment of Anatomy and Anthropology, Schooi of Medicine, Uhaiversit), of OccuPational and Environmental Heaith, JaPan, Kitakyushu 807, faPan

Abstract: The lungs of a rough toothed porpoise, Steno bredanensis, were $tudied from the corrosion anatomical viewpoint by preparing the corrosion cast ift sit". It is the most suitable meLhod of studying the three-climensional relationship of the tracheobronehial tree and the pulmonary vascular tree within the lungs, There is one lobe on each side, but

feur secondary bronchi on the right, and three secondary ones and a cardiac impression on the left. There are three eparterial bronchi: the tracheal bronchus and the second closest bronchus to the cranium on the right side; the closest bronchus ,to the cranium en the left, While the pulmonary arteries ge along almost the samel course of the tracheobronchial tree, the pulmonary veins come intersegmentally from the peripheral parts making a four-forked convergence ventrally. One dorsal vein adds to this conver- gence, resulting in a five-forked form.

Key tvords: corrosion anatemy, eparterial bronchus, rough toothed porpoise,

(Received 16 August 1980)

Introductien

Various patterns of the regional relationship between the tracheobronchia] tree and

the pulmenary vascular one in the lungs of sea mammals have been attracting the at-

tention of not a few investigators (Aeby, 1880; Boeckh, 1914; Huntington, 1920; Ping,

1926; Marcus, 1937; Arai, 1958; Brown, 1958; Sakai & Tsuneishi, 1962; Hojo, l975,

1979; Yamasaki', et al., 1977). Among their various patterns, the eparterial bronchus,

which was first described by Aeby, has been one of the rnain objects from the comparative

point of view, including human subjects,

There are many textbooks on .human anatomy in which the eparterial bronchus in humans is described, one being Grant:s Method of Anatomy (Basmajian, 1975). But, until now, there has been none on the eparterial bronchus in the lungs of the porpoise,

Steno bredanensis, family DetPhinidae, class Mammalia. That is to say, regarding

the lung$ of Steno bredanensis, the problem of the regional relationship between the

tracheobronchial tree and the pulmonary vascular one remains unsolved. Further, the comparative anatomical study of the lungs of Franciscana (PontoPoria blainvillei), compared with those other cetaceans, was recently made by Yamasaki et al.

(1977). But witheut regarding the corrosion cast they obtained conclusions only on the

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464 T. HoJo

ramifications and a few descriptiens on the regional relationship between them in their

study. In order te make clear and describe accurately the three-dimensional relationship

between them, the author thinks the most suitable method is to prepare the corrosien cast

of the lungs in situ.

In this paper the author describes some conclusions obtained by preparing the corrosion

cast of the lungs of the rough toothed porpoise and by referring to Tucker & Krementz

(1957), Arai (1958), Hejo (1975, 1979), and Yamasaki et al. (1977).

Materials and Methods

In order to make clear the three-dimensional relationship of the pulmonary vascular

tree to the tracheobronchial one, the author prepared the corrosion cast of the lungs of the porpoise in situ, injecting yellow resin into the most cranial part of the trachea, red resin into the pulmonary arteries, and blue resin into the pulmonary veins. The injection

technique was slightly changed from that of Hojo (1974, J.975). The inhaled lungs in situ were iinjected to prevent, as little as possible, the collapse of the shape. When the

injection materials hardened, the lungs were removed from the thorax and placed in a

strong solution of hydrochloric acid, until the lung tissue had been corroded. After

corrosion, they were washed by running water to make the cast of the tracheobrenchial

tree and the pulmonary vascular tree.

The subject used in this study was the rough toothed porpoise, Steno bredanensis

which was also used in the anatomical study of the liver by Hojo & Mitsuhashi (1975).

It was an adult male, 241 cm in body length, caught in the North Pacific Ocean neighbor-

ing Japan.

Results and Discussion

It is generally known that the lungs of the porpoise and the dolphin have no iobulation

on either side. In the author's observations the lungs of the rough toothed porpoise

which are bell-shaped, have no fissure on each side and the right lung is considerably

larger than the left.

As shown in Figs, 1 and 2, the tracheobronchial tree and the pulmonary vascular tree show an asymmetrical pattern. From the right lateral wall the tracheal bronchus leaves

the trachea at an angle of about 200, at the point about 70 mm craniad from the bifur-

cation of the trachea. The tracheal bronchus, 15 mm in diameter and 77 mm long,

gives off the tertiary bronchi which supplies the cranial part of the lung. Because the rough toothed porpoise has one lobe on each side and the tracheal bronchus supplies the

cranial part of the right lung, the tracheal bronchus is theught to be the secondary bronchus. The position of the Lracheal bronchus is more craniad than those of the lungs

of the PontoPoria, the inia and the Platanista which were reported by Yamasaki et al. (1977).

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EparterialBronchus in theRoughToothedPorpeise 461)

Fig,L Fig, 2.

Figs, 1 and 2. Ventral view of the porpoise lungs.

Fig. 3, Dorsal view of the porpoise lungs,

T: Trachea

ETB: Tracheal bronchus (Epartetial bronchus)

PB: Principal bronchus

A: Pulmonary artery

V; PuEmonary vein ESBR: The right second closest bron- chus to the cranium(Eparterial bronchus) ESBI): The left closest bronchus to the cranium (Eparterial bronchus). Fig. 3, AR and AL: Right and left pttlmonary artery

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466 T. HoJo

The trachea biiurcates two principal bronchi; the right and the left, and they make

an angle of 250.

In the right lung, the second closest secondary bronchus to the cranium branches ofii

dorsolaterally about 10 mm long and 12 mrn in diameter. About 30 mm distant caudad

from the branching site of the second closest secondary bronchus to the cranium, the

principal bronchus gives off two seconclary bronchus, the ventral and the dorsal, which

become the third closest secondary brQnchus to the cranium. The ventral one is 10 mm

in diameter and 10 mm long. The dorsal one, almost the same size as the ventral one,

branches off slightly caudad.

Regarding the bronchial tree, Brown (1958) pointed out in his explanation of the

preparation ef the resin cast in Proceedings of the Anatomical Society that t.he porpoise

Iungs show a distinctly unequal bronchial pattern, including the tracheal bronchus on the right side. These results are almost the same as the present author's. But the kinds

of porpoises used jn Brown's study are unknown and the relationship between the bronchial

tree and the pulmenary vascular tree was also not shown. The pulmonary artery biturcate at the position of about 26 mm distant caudad from

the bifurcatien of the trachea, is situated ventra]ly to the leit prlncipal bronchus. As

shown in Fig. 1, the pulmonary artery in the right Lung gives off its first branch into the

cranial part of the right lung goin.cr across the right principal bronchus and the tracheal bronchus, situated ventrally to the bronchial tree. After the pulmonary artery gives off the closest braneh to t'he cranium ancl goes across the right principal bronchus, it passes

between the second clesest secondary bronchus to the cranium and the third closest

secondary bronc.hus to the cranium, and goes caudad Iying dorsally to the third closest

secondary bronchus to the cranium in the dorsolatera] course along that oi the right

principal bronchus (Fig. 3).

On the other hand, the left lung has no tracheal bronchus. The closest secondary

bronchus to the cranium, 15 inm in diameter and 20 mm long, supplying the cranial part

of the leit lung, brancbes off dorsolat.erally at the almost same positio]i of the branching

of the second c]osest secondary bronchus to the cranium in the right lung. But this

closest secondary bronchtis of the left lung is considerably thicker, larger, and longer

than the second closest secondary bronchus to the cranium in the right lung. Further,

the iormer exLends more craniad than the latter.

Ill each side of the lungs the number and shapes of other secondary bronchi are observr-

ed, but the interrnediate bronchi in the medial side start from the lefL principal bronchus.

These intermediate secondary bronchi are thicker and longer in the lelt lung than those

in the right lung. There are more than three in the left. The feature of the rough

toethed porpoise is that ]'t has more-than-three medial intermediate secondary bronchi

in the left lung. This characteristic feat/ure is not observed in other sea mammals such

as the seal (Arai, 1958; Sakai & Tsuneishi, 1962), the harbor seal (Hojo, l975), and the otary (Hojo, 1979). In addition to this, the left principal brencus shows censiderable

concavity in the medial side. This concavit}i is the cardiac impression.

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Eparterial Bronchus in the Rough Toothed Porpoise 467

The pulmonary artery in the left lung branches off from the bifurcation of the

pulmonary artery and goes ventrally to the closest secondary bronchus, giving off the

colsest branch to the cranium. After that, the pulmonary artery passes between the

closest secondary bronchus and the second closest secondary one, and goes caudad Iying dorsally to the latter, in a course aiong that of the left principal bronchus. The course of the left pulmonary artery is almost the same as that of the right pulmonary artery. The position where the pulmonary artery passes between t.wo secondary bronchi from the

ventral side to the dorsal, is almost the same on both sides of the lungs.

According to Aeby's description, we can also consider this position of the secondary broncus cranial to the pulmonary artery as the eparterial bronchus. In the lungs of the porpoise, we can ebserve three eparterial bronchus bilaterally: the tracheal bronchus

and the second closest secondary bronchus to the craniuin in the right iung; and the closest

secondary brenchus to the cranium in the left.

Further, as in the harbor seal, there is ne secondary bronchus corresponding to one

that suppiies the cardiac lobe in the lungs of the dog, cat, otary and others, in the lungs

of the rough toothed porpoise. . As for the pulmonary veins, they can be summed up briefiy. They come inter-

seg:mentally from peripheral parts making a four-forked convergence ventrally. One

dorsal vein adds to this convergence, resuj.ting in a five-for]

Acknowledgments

For the fresh lungs of the adult rough toothed porpoise, Steno bredanensis, used in

this stucly, the author is deeply indebted to Dr. F. Yaniasaki, Depart,ment of Biology, ' Sapporo Medical College.

References

Aeby, C. (l880): Der Bronchialbaum der Stiugethiere und des Menschen nebst Bemerkungen tiber den Bronchialbaurn der V6gel und Reptilien. Leipzig. (cited from Boeckh, 1914), Arai, S. C1958): An anatomical study on the bronchi and pulmonary blood vessels. Jikei, Med.

J., 5: 162-18Z Basmajian, J. V. (1975): GranL's Method of Anatomy, 9th edi, Williams & Wilkins, Baltimore, 405

pp.Boeckh, R. (1914): I, Manimalia. Die Entwicklung der Saugerlunge, Morph. Jahrb., 48:4]5-448, Brown, D, (1958); The bronchial tree in aquatic marnmals. J, Anat., 92: 656.

Hojo, T. (1974): A reexamination on making anatomical corrosion casts, especially irom the lung. Sapporo Med, J., 43: 1-4. (in Japanese with English summary) Hojo, T. (1975): An anatomical study on trachea, bronchi and pulmonary vessels of the harbor seal

vittttina) with a corrosion cast, (Phoca Acta Anat. Nippon,, 50: 229-235. Hojo, T. (1979): A corrosive anatomy on the otary (Otaria byfonia) and some other sea mammals. Acta Anat, Nippon, 54: 218-219. (ill Japanese without Engljsh summary)

Hojo, T, & Mitsuhashi, K. (1975): Corro$ions-anatomy of the intrahepatic vascular systems of a

rough toothed porpuise, Sieno bredantimsis, Acta Anat. Nippon, 50; 258-261.

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468 T ．HOJO

Huntington， G ． S．（1920）： Acritique of the theories of pul 皿 onary evolution in the ma 皿 皿 alia ． Aln ．

．Anat 27 ： 99−201． J ，，

： In ： vergleichenden Anatomie Wirbeltiere． Bolk L ． Marcus ，H ．（1937） Lungen． Handbuch der der （ ，

et al ed ＆ Berlin und Wlen ．， ．） Urban SGhwarzenberg， ．pp ，968977． ・ Ping， C．（1926）： On son ／e parts of the visceral aDatomy of the porpoise ， Neomeris phocoenoides． − Anat， Rec，，33； 13 28．

Sakai K ＆ R 1962 ： Azarashi no k圭kan oyobi haidozyomyaku no bunkigata Ili tsuite ， ， Tsuneishj， ．（ ） 一 （On the pattern of the tracheobronchial 量．ree and pul1 皿 onary vessels of the seal ）． Tokyo Jikei − Idai Kaibo Gyosekishu，24： 1 8．（in Japanese without English summary ）、 一 Tucker ， J． L ．， Jr．＆ Kre 皿 entz ， E ． T ．（1957）： Anatol 皿 ical corrQsion specimens 、 n ， Broncho − pulmonary anatomy in the dog． Anat ． Rec．，127： 667 676． Yamasaki ， F ．， Takahashi ， K ． ＆ Kamiya ， T ， （1977 ） ： Lungs of Franciscana（PontoPoria blainviUei），

wi 出 special references to their external aspects ， weights and bronchial ra 皿 i丘cations ， Okajimas − Fol． Anat， Jap．，53： 337 357、

シ ワ ハ イ ル カ Steno bredanensisの 動 脈 上 気 管 支 の 腐 蝕 解 剖 学 的研 究

ゴ匕 イ廉 ト悵巨 二幸 一 産業医禾斗人 学第 解 剖学 教室

要 旨 ： シ ワ ハ イ ル カ StenO bredanensis の 肺 ｝こ つ い て ，比 較 解 剖 学 的 見 地 か ら ， in 5itu の 状 態 一 で 腐 蝕 標 本 を 作 っ て 行 う窗 蝕 解 剖 学 的 な 研 究 を 行 っ た ．こ れ は ，肺 内 の 気 管気 管支樹 お よ

び lllli動 静 脈 の 立 体 的 研 究 を 行 う た め に ，最 適 な 方 法 で あ る ．シ ワ ハ イ ル カ の 肺 は 左 右 と も

1 葉 か ら成 り立 つ が ，2 次 的 な 気 管 支 に つ い て み る と 右 肺 に 4 本 ，左 肺 に 3 本 あ り，心 切

痕 は 左 肺 に あ る ．動 脈 ヒ気 管 支 は 全 部 で 3 本 あ ）1 ，右 肺 に お け る 気 管 気 管 支 と 2 番 日 に 頭 ・ 側 1L あ る 気 管 支 お よ び 左 肺 に お け る 最 も頭 側 の 気 管 支 で あ っ て ，い ず れ も ヒ トの 菓 気 管 支

（2 次 的 気 箸 支 ） に 相 当 す る もの と 見 ら れ る ， 肺 動 脈 は ， 気管支 樹 に 沿 っ て 走 る が ， 肺 静 ・ 脈 は 末 梢 部 か ら 区 域 間 を 走 っ て 1 分 岐 の 型 を な し て 腹 側 に 集 合 し， さ ら に こ の 集 含 点 に 背 側 か ら も 1 本 の 分 枝 が 加 わ ），結 局 5 分 岐 の 形 を 形 成 す る ， ．− J．UOEH （産 業 医 大 誌 ），2 （4 ）： 463 468 （1．980）

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