Final answer:
The xiphoid process is the inferior most aspect of the sternum, which also includes the manubrium and body. The manubrium is at the top, and the xiphoid process becomes ossified as one ages.
Step-by-step explanation:
The xiphoid process is the inferior most aspect of the sternum. The sternum is an elongated bony structure that anchors the anterior thoracic cage and consists of three parts: the manubrium, body.
The manubrium is the wider, superior portion, which articulates with the clavicles and the first ribs. The body of the sternum is the longest part, and it has direct attachments from the costal cartilages.
The inferior tip, known as the xiphoid process, is cartilaginous early in life but becomes ossified during middle age.