Everything to know about rib cage

Everything to know about rib cage

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RIB CAGE

Rib cage also known as Thoracic cage is the arrangement of ribs in such a way that it forms a cone shaped structure that is narrow above and broad below. In other words it is the inner framework of the human chest.It also acts as shield and protects heart and lungs.
 Let us try to understand it under the following topics

1). MAKE UP OF THE RIB CAGE.

Rib cage is made up of three basic structures that articulate and binds with each other.
In the front it is the sternum and posteriorly twelve thoracic vertebrae forms the anchor.
Between these two ends twelve ribs on each sides forms the cage structure.
Only upper seven ribs articulate with the sternum hence we can call it as TRUE RIBS.
8th, 9th and 10th ribs joins the costocartilage of the rib above and is know as FALSE RIBS.
11th and 12th ribs are free in the front and hence are called FLOATING RIBS.
JOINTS THAT GIVE MOBILITY TO THE RIB CAGE
Costo-vertebral; costo tranverse; manubriosternal and chondrosternal are the joints that are formed; ribs being the common partner in them except manubriosternal joint.
The above joints together makes rib cage mobile facilitating expansion of chest during breathing.

2)BIOMECHANICS OF RIB CAGE DURING BREATHING.

In children rib cage is highly elastic and ribs are more horizontal In adults it is more stiff and placed oblique.
PUMP HANDLE MOVEMENT: it is to be remembered that each rib acts as a lever. The anterior end of rib is lower than the posterior end. Hence during inspiration(taking deep breath), there is elevation of ribs, with it the anterior ends of ribs also move forward. This brings sternum up and down depicting the pump handle movement and hence the name.
BUCKET HANDLE MOVEMENT: It is the outward movement of shaft of the ribs during inspiration. This increases the diameter of the rib cage allowing lungs to expand.
CALIPER ACTION : is restricted mainly to lower ribs from 8th to 12th ribs. In inspiration these ribs move laterally that in turn increases the lateral diameter.3) THE ARTICULATION OF RIBS WITH THE THORACIC VERTEBRAE 
It is very much necessary to mention that the posterior end of the ribs articulating with the thoracic vertebrae forming costo vertebral and costo transverse joints.
COSTO VERTEBRAL JOINTS are 24 in number dividing into two parts.
Ribs 1,10,11,12 articulates with single vertebra while that of ribs 2 to 9 articulates with two adjacent vertebrae and intervening disc. To understand this we can assume that rib 2 joins with T1 and T2 ; rib 3 with T2 and T3 and so on till rib 9 which joins with T8 and T9.
COSTO TRANSVERSE JOINTS are between ribs and the tranverse process of vertebra of the same level for ribs 1 through 10.Ribs 11 and 12 do not articulate with the tranverse process hence there is no costotransverse joint at this levels.

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