Xiphoid process of sternum

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Bony elements of the sternum.

The xiphoid process, also known as the xiphisternum, is the smallest and most inferior of the three parts of the sternum. It is highly variable in shape, though it is typically thin and elongated, with its inferior end located at the level of the T10 vertebra. It is usually cartilaginous until around 40 years of age when it becomes more or less ossified.

The xiphoid process is the anterior limit of the thoracic outlet. Superiorly, it is continuous with the body of the sternum at the xiphisternal joint. Inferiorly, the linea alba extends from it to the pubic symphysis. The costoxiphoid ligaments attach to its anterior and posterior surfaces.

The xiphoid process also serves as an attachment point for several muscles. The sternal part of the diaphragm, when present, attaches to its posterior aspect. The medial fibers of the rectus abdominis, as well as the aponeuroses of the internal and external obliques, attach to its anterior surface. The aponeuroses of internal oblique also attaches to its borders, together with the aponeurosis of the transversus abdominis.