what is the thoracic cage and what is it formed by (4)?
The skeletal portion of the thorax, the thoracic cage, is a bony cage formed by
the sternum, costal cartilages, ribs, and the bodies of the thoracic vertebrae.
what are the functions of the thoracic cage?
The thoracic cage encloses and
protects the organs in the thoracic cavity and upper abdominal cavity.It also provides support for the bones of the shoulder girdle and upper limbs.
what is the sternum, where is it located, and what does it consist of?
The sternum, or breastbone, is a flat, narrow bone located in the center of the anterior thoracic wall and consists of three
parts that usually fuse by age 25.
what is the upper part called? what is the middle and largest part called? what is the lowest, smallest part called?
The upper part is the manubrium; the
middle and largest part is the body; and the lowest, smallest part is the xiphoid process.
what does the manubrium articulate with?
The manubrium articulates with the clavicles, first rib, and part of the second rib.
what does the body of the sternum articulate with?
The body of the sternum articulates
directly or indirectly with part of the second rib and the third through tenth ribs.
what does the xiphoid process consist of during infancy and childhood? it doesn't ossify completely until which age?
The xiphoid process consists of hyaline
cartilage during infancy and childhood and does not ossify completely until about age 40.
does the xiphoid process have ribs attached to it? what does the xiphoid process provide?
It has no ribs attached to it but provides attachment for some abdominal muscles.
what happens to the xiphoid process when the hands of a rescuer are incorrectly positioned during CPR?
If the hands of a rescuer are incorrectly positioned during cardiopulmonary resuscitation (CPR), there is danger of
fracturing the xiphoid process and driving it into internal organs.
how many pairs of ribs make up the sides of the thoracic cavity?
Twelve pairs of ribs make up the sides of the thoracic cavity.
what happens to the ribs in length from the 1st through 7th ribs? what happens to the ribs in length to the 12th rib?
The ribs increase in length from the first through seventh ribs, then decrease in length to the twelfth rib.
what does each rib articulate posteriorly with?
Each rib articulates posteriorly with its corresponding thoracic vertebra.
what do 1st through 7th pairs of ribs have and by what? what are these ribs called?
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.
what are the remaining 5 pairs of ribs called and why?
The remaining five pairs of ribs are termed false ribs because their costal cartilages either attach indirectly to the sternum or
do not attach to the sternum at all.
what do the cartilages of the 8th, 9th, 10th pairs of ribs attach to?
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.
what are the 11th and 12th false ribs also known as and why?
The eleventh and twelfth false ribs are also known as floating ribs because the costal cartilage at their anterior ends does not attach to the sternum at all.
what do floating ribs attach only posteriorly to?
Floating ribs attach only posteriorly to the thoracic vertebrae.
what are the spaces between ribs called and by what are they occupied?
Spaces between ribs, called intercostal spaces, are occupied by intercostal muscles, blood vessels, and nerves.