Thoracic cage

includes the thoracic vertebrae, ribs, sternum, and costal cartilage

The sternum has three parts:

manubrium, body, xiphoid process

Manubrium of sternum

top of sternum

body of sternum

the bony structure that forms the middle portion of the sternum

Xiphoid process of sternum

cartilaginous section at the lower end of the sternum, which is not attached to any ribs, and gradually ossifies during adult life.

How many pairs of ribs are there?

12 pairs of ribs

True ribs

first 7 pairs of ribs; attach directly to sternum

False ribs

5 pairs
-three pairs; do not attach to the sternum - they connect to the rib above them
-two pairs; do not attach to anything at their anterior ends

Important features of ribs

Costal angle
costal groove
intercostal spaces


end of the rib that meets with the vertebral column.

costal angle

designates the sharp turn of the rib.

costal groove

provides a passageway for blood vessels and intercostal nerves.


the major part of the rib.

intercostal spaces

which is the area between the ribs, are occupied by intercostal muscles.