ЛЕКЦИЯ № 14. Thoracic wall

There are 12 thoracic vertebrae. The vertebrae have facets on their bodies to articulate with the heads of ribs; each rib articulates with the body of the numerically corresponding vertebra and the one below it. The thoracic vertebrae have faces on their transverse processes to articulate with the tubercles of the numerically corresponding ribs. Sternum: the manubrium articulates with the clavicle and the first rib. It meets the body of the sternum at the sternal angel an important clinical landmark.

The body articulates directly with ribs 2-7; it articulates interiorly with the xiphoid process at the xiphisternal junction. The xiphoid process is cartilaginous at birth and usually ossifies and unites with the body of the sternum around age 40.

Ribs and costal cartilages: there are 12 pairs of ribs, which are attached posteriorly to thoracic vertebrae.

Ribs 1-7 are termed «true ribs» and attach directly to the sternum by costal cartilages.

Ribs 8-10 are termed «false ribs» and attach to the costal cartilage of the rib above. Ribs 11 and 12 have no anterior attachments, and are therefore classified as both «floating ribs» and false ribs. The costal groove is located along the inferior border of each rib and provides protection for the intercostal nerve artery, and vein, ribs 1, 2, 10, 11, and 12 are atypical. Muscles: external intercostal muscles.

There are 11 pairs of external intercostal muscles. Their fibers run anteriorly and inferiorly in the intercostal spaces from the rib above to the rib below.

These muscles fill the intercostal spaces from the tubercles of ribs posteriorly to the costochondral junctions anteriorly; they are replaced anteriorly by external intercostal membranes. Internal intercostal muscles: there are 11 pairs of internal intercostal muscles. Their fibers run posteriorly and inferiorly in the intercostal spaces deep to the external layer.

These muscles fill the intercostal spaces anteriorly from the sternum to the angles of the ribs posteriorly; they are replaced posteriorly by internal intercostal membranes.

Innermost intercostal muscles: the deep layers of the internal intercostal muscles are the innermost intercostal muscles.

These muscles are separated from the internal intercostal muscles by intercostal nerves and vessels.

Subcostalis portion: Fibers extend from the inner surface of the angle of one rib to the rib that is inferior to it.

Fibers may cross more than one intercostal space, Transversus tho-racis portion: Fibers attach posteriorly to the sternum. Fibers cross more than one intercostal space.

Internal thoracic vessels, branches of the subclavian arteries, run anterior to these fibers. Intercostal structures

Intercostal nerves: there are 12 pairs of thoracic nerves, 11 intercostal pairs, and 1 subcostal pair.

Intercostal nerves are the ventral primary rami of thoracic spinal nerves. These nerves supply the skin and musculature of the thoracic and abdominal walls.

Intercostal arteries: there are 12 pairs of posterior and anterior arteries, 11 intercostal pairs, and 1 subcostal pair.

Anterior intercostal arteries.

Pairs 1-6 are derived from the internal thoracic arteries.

Pairs 7-9 are derived from the musculophrenic arteries.

There are no anterior intercostal arteries in the last two spaces; these spaces are supplied by branches of the pos terior intercostal arteries.

Posterior intercostal arteries: the first two pairs arise from the superior intercostal artery, a branch of the costocervical trunk of the subcla vian artery.

Nine pairs of intercostal and one pair of subcostal arter ies arise from the thoracic aorta.

Intercostal veins: Anterior branches of the intercostal veins drain to the internal thoracic and musculophrenic veins.

Posterior branches drain to the azygos system of veins.

Lymphatic drainage of intercostal spaces: anterior drainage is to the internal thoracic (parasternal) nodes.

Posterior drainage is to the paraaortic nodes of the poste rior mediastinum.

New words

thoracic – грудной

wall – стенка

below – под

sternum – грудина

clavicle – ключица

xiphisternal – грудинный

true – правдивый

false – фальшивый

groove – углубление

above – над

anteriorly – раньше

intercostal – межреберный

subcostal – подкостный

portion – часть

transversus – поперечный

musculophrenic – мышечный грудобрюшной

paraaortic – парааортальный

mediastinum – средостение

Запомните следующее застывшее словосочетание.

I to watch _ TV

Если перед существительным стоит вопросительное или относительное местоимение, артикль опускается.

E. g. What colour is your cat?

I want to know what _ book you are reading.

Заполните пропуски, где необходимо.

1. My… aunt and my… uncle are… doctors.

2. They work at… hospital.

3. They get up at seven o'clock in… morning.

4. They go to… bed at eleven o'clock.

5. I work in… morning and in. after noon.

6. I don't work in… evening. I sleep at… night.

7. When do you leave… home for… school?

8. I leave… home at… quarter past eight in… morning.

9. What does your mother do after… breakfast?

10. She goes to… work.

11. Is there… sofa in your… living-room?

12. Yes, there is… cosy little… sofa in… living-room.

13. Where is… sofa? – It is in… corner of… room to… left of… door.

14. I like to sit on this… sofa in… front of… TV-set in… evening.

15. There is… nice coffee-table near… window.

16. There are… newspapers on… coffee-table.

17. There is… tea in… glass.

18. When do you watch… TV? – I watch TV in… evening.

19. We have… large colour TV-set in our… room.

20. There is. beautiful vase on… TV-set. There are… flowers in… vase.

Answer the questions.

1. How many thoracic vertebrae are there?

2. What does each rib articulate with?

3. What does the manubrium articulates with?

4. With how many ribs does the body articulates directly?

5. How many pairs of ribs are there?

6. How are termed ribs 1-7?

7. How are termed ribs 8-10?

8. How are classified ribs 11-12?

9. How many pairs of thoracic nerves are there?

10. What does intercostal nerves supply?

Make the sentences of your own using the new words (10 sentences).

Find the definite and indefinite articles in the text.