Skeletal system: thorax

Question 1

What does the term thorax refer to?

Answer 1

the entire chest

Question 2

What is the thoracic cage?

Answer 2

the skeletal portion of the thorax. It is a body cage consisting of the manubrum, sternum, costal cartilages, ribs & the bodies of the thoracic vertebrae

Question 3

What are the functions of the thoracic cage?

Answer 3

• encloses and protects the organs in the thoracic cavity and upper abdominal cavity
• provides support for the bones of the shoulder girdle and upper limbs

Question 4

What is the sternum?

Answer 4

a flat, narrow bone located in the center of the anterior thoracic wall and consists of three parts that usually fuse by age 25

• articulates directly or indirectly with part of the second rib and the third through tenth ribs

Question 5

What is above & below the sternum?

Answer 5

the manubrum is above
the xiphoid process is below

Question 6

What does the manubrum articulate with?

Answer 6

the clavicles, the 1st rib & part of the 2nd rib

Question 7

How many ribs are there in the thoracic cavity?

Answer 7

12

Question 8

Which ribs increase in length?

Answer 8

from the first through seventh ribs

Question 9

Which ribs decrease in length?

Answer 9

from the seventh to the 12th rib

Question 10

Which ribs have a direct anterior attachment to the sternum?

Answer 10

The first through seventh pairs of ribs have a direct anterior attachment to the sternum by a strip of hyaline cartilage called costal cartilage - these ribs are called true ribs

Question 11

Why are 5 pairs of ribs called false ribs?

Answer 11

because their costal cartilages either attach indirectly to the sternum or do not attach to the sternum at all. The cartilages of the eighth, ninth, and tenth pairs of ribs attach to each other and then to the cartilages of the seventh pair of ribs.

Question 12

Which ribs are called floating ribs?

Answer 12

11th & 12th

Question 13

Why are ribs 11 & 12 called floating ribs?

Answer 13

because the costal cartilage at their anterior ends does not attach to the sternum at all. Floating ribs attach only posteriorly to the thoracic vertebrae.

Question 14

What are intercostal spaces?

Answer 14

spaces in-between the ribs

Question 15

What do the bones in the thorax close & protect?

Answer 15

they enclose & protect organs in the thoracic cavity & upper abdominal cavity
It also provides support for the bones of the shoulder girdle and upper limbs.