Human Anatomy: Thoracic Skeleton

Thoracic Skeleton

• The thoracic skeleton consists of the sternum, 12 pairs of ribs, 12 thoracic vertebrae, and interconnecting joints.

Sternum

• The sternum is a flat bone located at the anterior aspect of the thorax, lying in the midline of the chest.
• The sternum is divided into three parts: the manubrium, body, and xiphoid process.

Ribs

• There are 12 pairs of ribs that form the protective 'cage' of the thorax.
• Ribs articulate with the vertebral column posteriorly and terminate anteriorly as cartilage (costal cartilage).
• Ribs have two roles: protecting internal thoracic organs and facilitating ventilation by moving during chest expansion to enable lung inflation.
• Each rib forms two joints: costotransverse joint and costovertebral joint.

Rib Attachments

• Ribs 1-7 attach to the sternum.
• Ribs 8-10 attach to the costal cartilages.
• Ribs 11 and 12 do not have an anterior attachment and end in the abdominal musculature.

Intercostal Spaces

• There are 11 intercostal spaces, each containing intercostal muscles (external, internal, and innermost) and the intercostal neurovascular bundle.
• The intercostal neurovascular bundle consists of the intercostal vein, artery, and nerve.

Thoracic Organs

• The thorax contains the heart, lungs, thymus, trachea, and esophagus.