Xiphisternum

Position in sternal structure

To understand the topography of the xiphoid process, it is necessary to examine the structure of the sternum (sternum) as a whole. The sternum is a flat bone located strictly in the frontal plane, forming the anterior wall of the thoracic cage. Normally, the chest has a convex shape anteriorly; the presence of concavity is considered a sign of congenital anomaly or acquired deformity.

Anatominically, the sternum is divided into three main parts:

1. Manubrium of sternum (manubrium sterni) — the upper section.
2. Body of sternum (corpus sterni) — the middle, most elongated part.
3. Xiphoid process (processus xiphoideus) — the pointed lower section, which is significantly thinner than the body of the bone.

All these elements are interconnected. For example, between the manubrium and the body, the sternal angle (angulus sterni, or Louis' angle) is formed, which corresponds to the level of the 2nd rib. The xiphoid process attaches to the lower margin of the sternal body, completing the osseous structure.

Anatomical variability and shape

Unlike the manubrium and the body of the sternum, which have a relatively stable structure in most people, the xiphoid process (referred to in some sources as Sappey's process) is characterized by extreme individuality.

Its shape is not strictly fixed and directly depends on the features of the appearance of ossification centers during embryonic development and subsequent growth. In anatomical practice, several typical variants of this process's structure are distinguished:

• Pointed — the classical shape resembling the end of a sword, from which the Latin name processus xiphoideus is derived.
• Bifid — the distal end of the process is divided into two parts (fork-shaped).
• Spatulate — the process has a wide base and a flattened shape, resembling a miniature spatula.
• With foramina — a through-hole (one or several) may be present in the center of the bone or cartilage tissue.

Topography and clinical significance

Despite its modest size, the xiphoid process performs important functions. From the perspective of topographical anatomy, it covers the phrenic nerve plexus, which in general practice is better known as the solar plexus.

The process acquires special significance in emergency medicine, serving as a key landmark for performing cardiopulmonary resuscitation (CPR). Correct positioning of the rescuer's hands is critical for the effectiveness of compressions and the prevention of injuries (such as fracture of the process itself or ribs).

Algorithm for finding the point for chest compressions:

1. Palpate the xiphoid process at the lower border of the sternum.
2. Measure 4 fingers up from its base toward the manubrium.
3. The found zone on the body of the sternum is the point of force application during compressions.

Important nuance: In men, when searching for the compression site, one can sometimes use the nipple level as a guide. However, this method is not used in women due to anatomical features, so the xiphoid process remains the only reliable landmark.

Class and exam questions

What else to study on this topic

• Structure of the manubrium of the sternum (manubrium sterni): jugular and clavicular notches.
• Depressions on the sternal manubrium for articulation with the cartilages of the first pair of ribs.
• Articulation of the sternum with the ribs: costal notches on the manubrium and body for the I–VII true ribs and part of the VIII rib.
• Sternal angle (Louis' angle) and its significance for determining the level of the II rib.
• Chest wall developmental anomalies: causes of anterior wall concavity formation.

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.