Visual Anatomy 視覚解剖学

肋間動脈　（ろっかんどうみゃく、英： posterior intercostal arteries ）

　・枝

　・参考となるサイト（ Wikipedia 、　イラスト掲載サイト）

　肋間動脈とは

　　「船戸和也のHP 」には以下のような解説文が見られる。

　　「大動脈が脊柱の左側にあるため、右肋間動脈は左よりも長く、また分岐後ただちに脊柱の前面を横切る

　　　ことになる。」

　以下は「船戸和也のHP 」の解説文の一部となる。

「現在の学名では intercostales の後に posteriores を付して命名されているが、日本名ではたんに肋間動脈とよぶ。古い学名BNAやINAでは Arteriae intercostales であった。Posteriores を付した理由は、内胸動脈より分枝する前肋間枝 ( Rami intercostales anteriores ) と対比した物である。」




肋間動脈/神経（模型図）

　以下は胸大動脈の枝の肋間動脈の走行の解説文となる。

　1 . 右側の肋間動脈は、胸大動脈が脊柱の左側寄りを下行しているために分岐後は脊柱を超えて、左側の胸大動脈は分岐後すぐに肋間隙に向かう。（胸腔内においては胸内筋膜に覆われながら横走する。）

　2 . 肋骨頚の位置で背側に走る背枝を分岐する。

　3 . 肋間隙では、最内肋間筋と内肋間筋の間を肋骨溝に沿って走り（肋間神経/肋間静脈と並走する）、すぐに上下の2枝に分かれる。

　　（下枝にあたる側副枝は斜め下方に走り、下位の肋骨の上縁に沿って前走し、内胸動脈からの枝と吻合する。）

　4 . 大きな主幹となる上枝は引き続き肋骨溝に沿って前走して外側皮枝を分岐する。

　5 . 主幹となる動脈はそのまま前走を続け、内胸動脈から分岐する前肋間枝と吻合して動脈弓を形成する。

　以下は肋間動脈の枝を簡単にまとめた図となる。

　以下は「 Wikipedia 」の解説文となる。

「 The intercostal arteries are a group of arteries that supply the area between the ribs ("costae"), called the intercostal space. The highest intercostal artery ( supreme intercostal artery or superior intercostal artery ) is an artery in the human body that usually gives rise to the first and second posterior intercostal arteries, which supply blood to their corresponding intercostal space. It usually arises from the costocervical trunk, which is a branch of the subclavian artery. Some anatomists may contend that there is no supreme intercostal artery, only a supreme intercostal vein.
The anterior intercostal branches of internal thoracic artery supply the upper five or six intercostal spaces. The internal thoracic artery ( previously called as internal mammary artery ) then divides into the superior epigastric artery and musculophrenic artery. The latter gives out the remaining anterior intercostal branches. Two in number in each space, these small vessels pass lateralward, one lying near the lower margin of the rib above, and the other near the upper margin of the rib below, and anastomose with the posterior intercostal arteries from the thoracic aorta.
【語句】

・ intercostal space ：肋間隙　　・ highest intercostal artery ：最上肋間動脈　　・corresponding ：対応する　　・ costocervical trunk ：肋頚動脈　　・ contend：論争する　　・ internal thoracic artery：内胸動脈　　・ superior epigastric artery：上腹壁動脈　　・musculophrenic artery ：筋横隔動脈　　・anastomose ：吻合する

　They are at first situated between the pleurae and the Intercostales interni, and then between the Intercostales interni and innermost. They supply the intercostal musclesand, by branches which perforate the Intercostales externi, the Pectoral muscles and the mamma.
The musculophrenic artery arises from the internal thoracic artery, directed obliquely downward and laterally, behind the cartilages of the false ribs; it perforates the diaphragm at the eighth or ninth costal cartilage, and ends, considerably reduced in size, opposite the last intercostal space.
It gives off intercostal branches to the seventh, eighth, and ninth intercostal spaces; these diminish in size as the spaces decrease in length, and are distributed in a manner precisely similar to the intercostal arteries from the internal thoracic artery.

【語句】

・ pleurae ：胸膜　　・ Intercostales interni ：内肋間筋　　・ Intercostales externi ：外肋間筋　　・ Pectoral ：胸筋　　・ mamma ：乳房　　・ musculophrenic artery ：筋横隔動脈　　・ false ribs ：仮肋　　・ perforate ：貫通する　　・ diaphragm ：横隔膜　　・ diminish ：減らす　　・ in a manner ：いくぶんか　　・ precisely ：正確に　

The musculophrenic artery also gives branches to the lower part of the pericardium, and others which run backward to the diaphragm, and downward to the abdominal muscles.
The posterior intercostal arteries are arteries that supply blood to the intercostal spaces.
There are eleven posterior intercostal arteries on each side.

　The 1st and 2nd posterior intercostal arteries arise from the supreme intercostal artery, a branch of the costocervical trunk of the subclavian artery.
　The lower nine arteries are the aortic intercostals, so called because they arise from the back of the thoracic aorta.

　The right aortic intercostals are longer than the left because of the position of the aorta on the left side of the vertebral column ; they pass across the bodies of the vertebrae behind the esophagus, thoracic duct, and azygos vein, and are covered by the right lung and pleura.

【語句】

・ pericardium ：心膜　　・ supreme intercostal artery ：最上肋間動脈　　・ vertebral column ：脊柱　　・ esophagus ：食道　　・ thoracic duct ：胸管　　・ azygos vein ：奇静静脈

The left aortic intercostals run backward on the sides of the vertebrae and are covered by the left lung and pleura; the upper two vessels are crossed by the left superior intercostal vein, the lower vessels by the hemiazygos vein.
Opposite the heads of the ribs, the sympathetic trunk passes downward in front of them, and the splanchnic nerves also descend in front by the lower arteries.
Each artery then divides into an anterior and a posterior ramus.
A given posterior intercostal artery travels along the bottom of the rib with its corresponding posterior intercostal vein, as well as the intercostal nerve of the given space. 　The vein is superior to the artery, and the intercostal nerve is inferior to it. Commonly, the mnemonic, "Van," is used to recall the order of the vein, artery and nerve, from superior to inferior.」