Xiphoid process

Xiphoid process Definition

It is a small cartilaginous projection of the lower portion of the breastbone or sternum that ranges in size from miniscule to several inches in length. The term “xiphoid” is derived from the Greek word xiphos, meaning straight sword. The tapered piece of bone is also known by the following names:

  • Metasternum
  • Xiphisternum
  • Ensiform process
  • Ensiform cartilage
  • Xiphoid cartilage

Xiphoid process Location

The bony outgrowth is situated in the center of the chest, precisely, below the nipple line, projecting downward from the point where the lowermost ribs join the sternum.

Xiphoid process Location

Xiphoid process Description

Metasternum exists as a single fragment of bone, but in the middle age it fuses to the body of the sternum with a fibrous joint. Therefore, in adults it is more of an ossified and hard structure. Unlike a joint, it is immovable in nature. The cartilage in the celiac plexus, a network of nerves that lies in the abdomen near the aorta, connects to the bony process for strengthening the latter, eventually joining the costal cartilage to the sternum. In fact, the flanks of manubrium, a triangular-shaped bone forming the superior portion of the sternum, and the main body, unite with the costal cartilages after forming a hollow dent. It joins the clavicles or shoulder blades on its upper border. In neonates and young infants, the bony projection is quite enlarged and appears as a prominent lump underneath the sternal notch. Due to this reason, many children have a sticking out sternum. It is sometimes medically considered to be at the level of 9th thoracic vertebrae and the T7 dermatome.

Based on certain hereditary factors, the bony extension may undergo morphological variations. For example, in some individuals the cartilaginous process bifurcates or splits into two segments. In many instances, medical researchers have discovered a perforated metasternum. Nevertheless, physiological modifications occur naturally and are not detrimental to the health of the individuals.

Xiphoid process Function

The ensiform cartilage serves as an important site of attachment for the following muscles:

  • Diaphragm: It is a thin dome-shaped skeletal muscle that separates the thoracic cavity from the abdomen to ensure normal respiration.
  • Rectus abdominis muscle: This is a long flat muscle of the anterior abdominal wall that supports the spinal muscles during strenuous activities as well as facilitates regular breathing movements. Most importantly, it keeps the intestines and other organs in the abdomen intact.
  • Transversus thoracis muscle: It is a flat muscle composed of transverse fibers that lines the anterior and lateral walls of the abdominal cavity.

The protruding structure also helps in locating the pericardium for drawing out fluid as a part of pericardiocentesis.

Xiphoid process Disorders

The bony prominence can get easily damaged as it is not protected by the ribcage. For this reason, a hard blow on the chest can inflict injuries on the cartilage piece. Such a situation has often been encountered during cardiopulmonary resuscitation (CPR), an emergency procedure often carried out on a patient whose breathing or heartbeat suddenly stops. Simply put, the life-saving technique involves chest compressions that may often break or fracture the xiphoid cartilage and puncture the diaphragm. A broken xiphoid process can be quite painful. If the person providing the aid lacks experience then there is a high possibility of a liver puncture and internal bleeding.

Xiphoidalgia or xiphoidynia is a rare syndrome marked by localized inflammation/swelling and tenderness of the ensiform process. Some of the other common indicators of the condition are:

  • Nausea
  • Abdominal discomfort
  • Chest soreness and pain, which radiates to the back, neck, and shoulders

The symptoms are more pronounced after a heavy meal, bending, twisting or coughing. Frequent lifting of heavy items and trauma on the chest are some of the causes of the condition. Administration of analgesics and coricosteroid injections are some of the curative options. Some individuals may have a benign or cancerous tumor on the bony structure that often manifests into a fatal disorder.

Pictures

Picture of Xiphoid process

 

Image of Xiphoid process

References

http://en.wikipedia.org/wiki/Xiphoid_process

http://www.innerbody.com/anatomy/skeletal/xiphoid-process-sternum

http://www.getbodysmart.com/ap/skeletalsystem/skeleton/axial/ribssternum/sternum/tutorial.html

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