Xiphoid

The xiphoid process /ˈzɪfɔɪd/, or xiphisternum or metasternum, is a small cartilaginous process (extension) of the lower part of the sternum which is usually ossified in the adult human. By age 15 to 29, the xiphoid usually fuses to the body of the sternum with a fibrous joint. Unlike the synovial articulation of major joints, this is non-movable. Much the way the first seven ribs articulate with the sternum, the cartilage in the celiac plexus joins on the xiphoid process, reinforcing it, and indirectly attaches the costal cartilage to the sternum. In newborn babies and young (especially slender) infants, the tip of the xiphoid process may be both seen and felt as a lump just below the sternal notch.