xiphisternum

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Bone: Xiphoid process
Lateral (side) border of sternum. (Xiphoid process labeled at bottom.)
Posterior surface of sternum. (Xiphoid process labeled at bottom.)
Latin	processus xiphoideus
Gray's	subject #27 121
MeSH	Xiphoid+Bone

The xiphoid process, 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.

Bifurcation

The xiphoid process can be naturally bifurcated, and sometimes perforated. These variances in morphology are inheritable, which can help group family members together when dealing with burial remains. These morphological differences pose no health risk, and are simply a difference in form.

Clinical significances

Pressure on the xiphoid process should be avoided when administering chest compressions in CPR, as this can cause the xiphoid process to break off, resulting in punctures or lacerations of the diaphragm. Additionally, the liver may be punctured, resulting in lethal hemorrhaging.

In 1712 was the first known case of a xiphoid disorder.^[1] The xiphoid process is considered to be at the level of the 9th thoracic vertebrae and the T6 dermatome.

Xiphoidalgia(Xiphodynia) is a syndrome distinguishable by pain and tenderness to the sternum. While some sources describe this disorder as rare, others suggest it is relatively common but overlooked by physicians. ^[2] Symptoms can include abdominal pain, chest pain, nausea and radiating pain to the back, neck, and shoulders. Lifting heavy objects or trauma to the chest may be the cause of this musculoskeletal disorder and pain may be heightened by bending or twisting. Anesthetic and steroid injections are commonly employed to treat this medical condition. ^[3]

Pericardiocentesis, the procedure whereby fluid is aspirated from the pericardium, often uses the xiphisternum as an anatomical landmark by which this procedure is carried out. ^[4]

Xiphoid process in birds

In birds, the xiphoid process is a long structure, often following the direction of the carinatae.

Etymology

The word derives from the Greek word xiphos for straight sword, the tip of which the process somewhat resembles.

Additional images

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  Location of the xiphoid process on the rib cage.

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  The human rib cage.

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  Anterior surface of sternum and costal cartilages.

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  The diaphragm. Under surface.

References