Xiphoid process
Processus xiphoideus
The small, pointed lower tip of the breastbone, cartilage in youth and slowly turning to bone with age.
At a glance
- English
- Xiphoid process
- Latin (TA2)
- Processus xiphoideus
- System
- Bone
- Region
- Thorax
- Side
- Single, on the midline
- Muscles on it
- Transversus thoracis
About the xiphoid process
The xiphoid process is the smallest and lowest of the three parts of the sternum. Its name comes from the Greek for a sword, as it forms the point of the sword-shaped breastbone. It hangs from the lower border of the body of the sternum at the xiphisternal joint, at roughly the level of the ninth thoracic vertebra, and lies in the notch between the converging seventh costal cartilages, at the top of the epigastric region.
It varies more than any other part of the sternum. It may be broad or thin, pointed, rounded, forked or bent forwards or backwards, and it sometimes contains a hole. In children it is cartilage; it ossifies slowly from a central core, often not until middle age, and in older people it is usually fused to the body. Its upper side edges share a small half-facet with the body for part of the seventh costal cartilage.
Though small, it is an attachment for several structures. On its front, the linea alba and the aponeuroses of the abdominal muscles reach it, with rectus abdominis close by on the cartilages; on its back, a slip of the diaphragm arises and transversus thoracis spreads upwards. The inferior sternopericardial ligament tethers the fibrous pericardium to it, and costoxiphoid ligaments bind it to the seventh cartilages. Behind and below it lie the left lobe of the liver and the heart's lower surface, which is why the xiphoid region is a route into the pericardial sac.
The tip can be felt in the midline as a small hard knob at the lower end of the sternum. It is a guide for hand position in cardiopulmonary resuscitation: hands set too low may break the process and press it into the liver, causing bleeding. A prominent or bent xiphoid is sometimes mistaken for a lump in the upper abdomen.
Function and supply
- Function
- Gives a fixed point at the front of the trunk for the diaphragm and the abdominal wall.
- Nerve supply
- Not innervated as a muscle is; overlying skin and periosteum are supplied by anterior cutaneous branches of the sixth and seventh intercostal nerves.
- Blood supply
- Branches of the musculophrenic and superior epigastric arteries, the end branches of the internal thoracic arteries.
Anthromica
See the xiphoid process where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
