The xiphoid process , or xiphisternum or metasternum, is a small

cartilaginous Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck a ...

process (extension) of the inferior (lower) part of the

sternum The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sha ...

, which is usually ossified in the adult human. It may also be referred to as the ensiform process. Both the Greek-derived ''xiphoid'' and its Latin equivalent ''ensiform'' mean 'swordlike' or 'sword-shaped'

Structure

The xiphoid process is considered to be at the level of the 9th thoracic vertebra and the T7 dermatome.

Development

In newborns and young (especially small) infants, the tip of the xiphoid process may be both seen and felt as a lump just below the sternal notch. At 15 to 29 years old, the xiphoid usually fuses to the body of the sternum with a

fibrous joint In anatomy, fibrous joints are joints connected by fibrous tissue, consisting mainly of collagen. These are fixed joints where bones are united by a layer of white fibrous tissue of varying thickness. In the skull the joints between the bones ...

. Unlike the synovial articulation of major joints, this is non-movable. Ossification of the xiphoid process occurs around age 40.

Variation

The xiphoid process can be naturally bifurcated or sometimes perforated (xiphoidal foramen). 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.

Other animals

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

keel The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in Br ...

Function

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. The xiphoid process is involved in the attachment of many muscles, including the abdominal diaphragm, a muscle necessary for normal breathing. It also anchors the rectus abdominis muscles ("abs").

Clinical significance

Pressure on the xiphoid process should be avoided when administering chest compressions in

cardiopulmonary resuscitation Cardiopulmonary resuscitation (CPR) is an emergency procedure consisting of chest compressions often combined with artificial ventilation in an effort to manually preserve intact brain function until further measures are taken to restore spont ...

(CPR), as this can cause the xiphoid process to break and detach, resulting in punctures or lacerations of the

diaphragm Diaphragm may refer to: Anatomy * Thoracic diaphragm, a thin sheet of muscle between the thorax and the abdomen * Pelvic diaphragm or pelvic floor, a pelvic structure * Urogenital diaphragm or triangular ligament, a pelvic structure Other * Diap ...

. Additionally, the liver may be punctured, resulting in deadly internal

bleeding Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...

. 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. This is a musculoskeletal disorder that has the ability to produce a constellation of symptoms that can mimic a number of common abdominal and thoracic disorders and diseases. Symptoms can include abdominal pain, chest pain,

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of th ...

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. The earliest known case of this was noted in 1712. After age 40, a person may become aware of their partially ossified xiphoid process and mistake it for an abnormality. Pericardiocentesis, the procedure whereby fluid is aspirated from the

pericardium The pericardium, also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong connective tissue (fibrous pericardium), and an inner layer made ...

, often uses the xiphoid process as an anatomical landmark by which this procedure is carried out. Final CD

Etymology

The word ''xiphoid'' derives from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

word ''

xiphos The ''xiphos'' ( grc, ξίφος ; plural ''xiphe'', grc, ξίφη ) is a double-edged, one-handed Iron Age straight shortsword used by the ancient Greeks. It was a secondary battlefield weapon for the Greek armies after the dory or javelin. ...

'' for straight sword, the tip of which the process somewhat resembles. The ''xiphoid process'' is a translation of Latin ''processus xiphoides''.Siebenhaar, F.J. (1850). ''Terminologisches Wörterbuch der medicinischen Wissenschaften.'' (Zweite Auflage). Leipzig: Arnoldische Buchhandlung.Triepel, H. (1910). ''Die anatomischen Namen. Ihre Ableitung und Aussprache. Mit einem Anhang: Biographische Notizen.''(Dritte Auflage). Wiesbaden: Verlag J.F. Bergmann. The writings of the Greek

physician A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...

Galen Aelius Galenus or Claudius Galenus ( el, Κλαύδιος Γαληνός; September 129 – c. AD 216), often Anglicized as Galen () or Galen of Pergamon, was a Greek physician, surgeon and philosopher in the Roman Empire. Considered to be o ...

Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with the assistance of. Roderick McKenzie.'' Oxford: Clarendon Press. refer to ''Os xyphoides'' a translation of ξιφοειδές ὀστοῦν. Classical Latin ''os'' and Ancient Greek ὀστοῦν both mean bone, while ξιφοειδές means sword-shaped.

Additional images

File:Xiphoid process animation.gif, Position of xiphoid process (shown in red) File:Xiphoid process below2.png, Close up. File:Xiphoid_process_-_close-up_-_animation.gif, Shape of a xiphoid process (animation)

References

External links

{{DEFAULTSORT:Xiphoid Process Bones of the thorax