xiphisternum

The xiphisternum, also known as the xiphoid process, is a small, cartilaginous projection extending from the lower part of the sternum (breastbone). It is the most inferior and smallest part of the sternum. In infants and young children, the xiphisternum is often made of cartilage, but it gradually ossifies and fuses with the body of the sternum in adulthood.

The shape and size of the xiphisternum can vary significantly between individuals. It can be pointed, bifid (forked), or even perforated. Functionally, the xiphisternum serves as an attachment point for several muscles, including the diaphragm and abdominal muscles, which play crucial roles in respiration and core stability. While it is not directly involved in protecting vital organs like the upper parts of the sternum, its muscular attachments are essential for movement and bodily function.

In certain medical procedures, such as cardiopulmonary resuscitation (CPR), care must be taken to avoid excessive pressure on the xiphisternum. Direct or forceful pressure applied to this area can lead to its fracture or detachment, potentially causing internal injury to organs like the liver. Anatomically, the xiphisternum is located at the level of the ninth thoracic vertebra.