Sternum

A flat bone located in the center of the chest, connecting to the ribs and providing structure to the ribcage.

The sternum, commonly referred to as the breastbone, is a long, flat bone that forms the anterior part of the ribcage. It serves as a central anchor point for the ribs, specifically the true ribs, which attach directly to it, while the false ribs attach indirectly through cartilage. The sternum is composed of three parts: the manubrium, the body, and the xiphoid process, which collectively play a crucial role in protecting vital organs located in the thoracic cavity, such as the heart and lungs.

Terminologia Anatomica

sternum

System

Skeletal system

Function

The sternum plays several key roles within the body. As a critical component of the ribcage, it provides structural support and stability to the chest while safeguarding vital organs against trauma. One of its primary functions is to facilitate the respiratory process, as its articulation with the ribs allows for the expansion and contraction of the thorax during breathing. Moreover, the sternum serves as an attachment point for important muscles, including the pectoralis major and the sternocleidomastoid, which are vital for upper body movement and stability. Additionally, the sternum's role in immunity is noteworthy; it houses the red bone marrow within its cancellous (spongy) structure, which is essential for the production of blood cells and the functioning of the immune system.

Location

The sternum is located in the center of the anterior thoracic wall. It extends vertically from the base of the neck down to the upper abdomen, situated beneath the clavicles and in front of the thoracic vertebrae. The sternum's three parts are oriented as follows: the manubrium is the uppermost section, which articulates with the clavicles and the first two pairs of ribs. The longest section, the body, connects to the manubrium and continues downward to meet the xiphoid process, the small cartilaginous extension at the inferior end of the sternum. This arrangement places the sternum in close proximity to the heart and lungs, emphasizing its protective role.

Did You Know?

The sternum is one of the few bones that can be used for marrow biopsy, allowing medical professionals to assess blood disorders.
The xiphoid process can vary in shape and is sometimes cartilaginous in young people, gradually ossifying into bone as one ages.
In humans, the sternum is typically around 15 to 20 centimeters in length, though it can vary based on individual anatomy.
The sternum is often used as a landmark for medical procedures, such as cardiopulmonary resuscitation (CPR).