Bones Of the Thorax: Ribs and SternumAlso known as the Bony Thorax, or Thoracic Cage, it consists of the Ribs and the Sternum. The thorax plays a major role in protecting the organs (especially the heart) and supporting the shoulder girdle. It also provides attachment site foe the muscles of the back, chest, and shoulders.
Sternum
The Sternum runs vertically down the middle of the chest and connects with many of the Ribs. It consists of three sections: the Manubrium, the Body, and the Xiphoid Process. The Manubrium is at the top and articulates with the Clavicle, and the first two pairs of ribs. The Body is the largest section, and articulates with the cartilage of Ribs 2 to 7. The Xiphoid process can be found at the lowest point where the ribs meet. It acts as an attachment site to some of the Abdominal muscles.
Ribs
There are twelve pairs of Ribs, each forming attachments to the Thoracic Vertebrae. The first seven pairs of Ribs are known as True or Vertebrochondral Ribs. The other five pairs are known as False Ribs because they don’t attach directly to the sternum. Ribs 8-10 attach by connecting to the cartilage of Rib 7, and are also known as Vertebrochondal Ribs. Ribs 11-12 have absolutely no connection to the Sternum and are subsequently known as Floating or Vertebral Ribs.
A. First Rib The highest of the 'True Ribs'. It articluates with T1, and the Manubrium via Costal Cartilage.
B. Costal Cartilage
The Cartilage that attaches the Ribs to the Sternum
C. Seventh Rib
The lowest of the 'True Ribs'. It articulates with T7, and the Sternum
D. Eighth Rib
The highest of the 'False Ribs'. It articluates with T8, and the Sternum
E. Tenth Rib
The lowest of the ribs that articulate with the Sternum. It also articulates with T10
F. Eleventh Rib
The highest of the floating ribs. It only articulates with T11
G. Twelth Rib
The lowest of the floating ribs. It only articulates with T12
H. T12
For information go to: Spine
I. Xiphoid Process
Also known as the 'Xiphisternum', the Xiphoid Process articulates with the Sternum and serves as an attachment point for the Diaphragm and Abdominals.
J. Body of Sternum
The mid-portion of the Sternum. It has notches on both sides that serve as attachment points for the cartilage of the third to seventh Ribs.
K. Manubrium
The upper part of the Sternum. It articulates with the Clavicles, and the first and second Ribs.
L. Clavicular Notch
The articulating surface for the Manubrium and Clavicle.
M. Jugular Notch
An indentation at the top of the Manubrium. It's usually in line with the disc between the second and third Thoracic vertebrae.