important bony landmarks of sternum with reference to its parts, sternal angle and its importance in clinical practice

The sternum, or breastbone, is a flat bone located in the anterior midline of the thoracic cage. It is divided into three parts: the manubrium, the body (gladiolus), and the xiphoid process. The sternal angle, also known as the angle of Louis, is a prominent landmark on the sternum. Here are the important bony landmarks of the sternum with reference to its parts and the sternal angle:

Parts of the Sternum:

1. Manubrium:
   • The superior portion of the sternum.
   • Articulates with the clavicles and the first two pairs of ribs.
   • Contains the jugular notch (suprasternal notch) at its superior border.
2. Body (Gladiolus):
   • The central and longest part of the sternum.
   • Articulates with the costal cartilages of the second to seventh ribs.
3. Xiphoid Process:
   • The smallest and most inferior portion.
   • Usually cartilaginous in youth, gradually ossifying with age.
   • Can be a reference point for the inferior limit of the heart.

Sternal Angle (Angle of Louis):

• Location:
  • The sternal angle is located at the junction between the manubrium and the body of the sternum.
• Characteristics:
  • Represents the level of the intervertebral disc between the fourth and fifth thoracic vertebrae.
  • Palpable and can be easily identified by feeling for a horizontal ridge on the anterior surface of the sternum at the level of the second rib.

Importance in Clinical Practice:

1. Landmark for Counting Ribs:
   • The sternal angle is used as a reference point for counting ribs and intercostal spaces.
   • The second rib articulates with the sternal angle, making it a consistent starting point for rib numbering.
2. Thoracic Surgery:
   • Surgeons use the sternal angle as a landmark during procedures such as thoracotomies.
   • It helps locate important structures in the thoracic cavity.
3. Identification of Thoracic Vertebrae:
   • The sternal angle corresponds to the level of the disc between the fourth and fifth thoracic vertebrae.
   • Clinically useful for locating the thoracic spine during physical examinations and radiological studies.
4. Identification of Tracheal Bifurcation:
   • The sternal angle marks the level of the tracheal bifurcation into the right and left main bronchi.
   • It serves as a useful reference for airway management.
5. Cardiac Examination:
   • The sternal angle provides an approximate reference for the level of the heart and great vessels.
   • Clinicians may use it as a guide during cardiac examinations and the placement of medical devices.

Understanding the bony landmarks of the sternum, especially the sternal angle, is crucial for healthcare professionals in various medical fields. It aids in accurate anatomical orientation, clinical assessments, and surgical procedures involving the thoracic cavity.