Muskullarning tuzilish, funksiyalari va yoshga oid xususiyatlari

The bones of the thorax enclose the thoracic cavity, which has an inlet and an outlet (apertura superior thoracis, apertura inferior thoracis). The thorax protects the organs of the thoracic cavity and is formed by the breastbone (sternum), the ribs (costae), and the thoracic spine (Fig. 4.15). The sternum is a flat bone and consists of the manubrium (handle), body (corpus) and a variously shaped xiphoid process (Fig. 4.16). Normally the thoracic cage is composed of 12 pairs of ribs, of which the first seven pairs, also called true ribs, reach the sternum. Of the remaining five pairs of ribs, the 8th, 9th, and 10th are a part of the structure of the costal margin.

• The bones of the thorax enclose the thoracic cavity, which has an inlet and an outlet (apertura superior thoracis, apertura inferior thoracis). The thorax protects the organs of the thoracic cavity and is formed by the breastbone (sternum), the ribs (costae), and the thoracic spine (Fig. 4.15). The sternum is a flat bone and consists of the manubrium (handle), body (corpus) and a variously shaped xiphoid process (Fig. 4.16). Normally the thoracic cage is composed of 12 pairs of ribs, of which the first seven pairs, also called true ribs, reach the sternum. Of the remaining five pairs of ribs, the 8th, 9th, and 10th are a part of the structure of the costal margin.

I ch k i q o v u r g’ a l a r a r o m u s k u l l a r (m. m. intercostales interni) ning tolasi pastdan yuqoriga va oldinga yo’nalgan bo’ladi. Ichki qovurg’alararo muskullar to’sh suyagidan qovurga burchagigacha joylashgan. U qisqarganda qovurralar­ni pastga tortib, nafas chiqarishda ishtiroq etadi.

• I ch k i q o v u r g’ a l a r a r o m u s k u l l a r (m. m. intercostales interni) ning tolasi pastdan yuqoriga va oldinga yo’nalgan bo’ladi. Ichki qovurg’alararo muskullar to’sh suyagidan qovurga burchagigacha joylashgan. U qisqarganda qovurralar­ni pastga tortib, nafas chiqarishda ishtiroq etadi.
• D i a f r a g m a (diaphragma) ko’krak va qorin bo’shliqlari orasidagi muskulli parda bo’lib, gumbaz shaklida tuzilgan. Uning muskul tutamlari qovurg’alarning pastki yoyidan, bel umurtqalaridan va to’sh suyagining o’simtasidan boshlanadi. Bel umurtqalaridan boshlangan qismi 3 juft oyoqcha hosil qiladi. Muskul tolalari yuqoriga aylana shaklida ko’tarilib, aponevroz gumbaz hosil qiladi. Diafragma qisqarganda, gumbaz pastga tushadi va ko’krak qafasi kengayib, nafas olish harakati bajariladi, bo’shashganda esa ko’krak qafasi torayib, nafas chiqarish sodir bo’ladi. Diafragmaning muskul qismida qizilo’ngach bilan aorta o’tadigan, pay qismida pastki kovak vena o’ta­digan teshiklar bo’ladi.