sternum anatomy

Sternum Anatomy Definition

Learning about the sternum will help you understand how the thoracic cage functions.The sternum has several critical roles, including:

• Protecting vital organs such as the heart and lungs
• Serving as an anchoring structure for the ribs and clavicles
• Assisting in the respiratory process by providing support

Anatomy of Sternum Regions

The sternum is divided into three regions, each with specific characteristics and roles within the chest structure. Here's a brief overview of those regions:Manubrium: The uppermost and broadest section of the sternum, forming the top part of the chest, which connects to the clavicles and the first pair of ribs.Body: Also known as the 'gladiolus,' this elongated middle section connects to the manubrium at its upper end and the xiphoid process at its lower end. It serves as a major attachment point for the true ribs.Xiphoid Process: A small, cartilaginous section at birth that typically ossifies in adults. It forms the lower tip of the sternum and has limited articulation.

Anatomy of Ribs and Sternum

Understanding the interaction between the ribs and sternum is essential in grasping how your thoracic skeleton plays a role in protection and respiratory function. The ribs are not only for protection but also crucial in enabling breathing by expanding and contracting the chest cavity.

Structural Connection Between Ribs and Sternum

The ribs connect to the sternum via cartilage, providing flexibility and strength. This connection forms a central part of the rib cage, protecting vital organs such as the heart and lungs.Here's a brief breakdown of this connection:

• Sternum: The centerpiece of the chest, anchoring the rib cage
• True Ribs (1-7): Directly attached to the sternum via costal cartilage
• False Ribs (8-10): Connect indirectly to the sternum through cartilage of the rib above
• Floating Ribs (11-12): Not connected to the sternum but anchored at the back by the spine

Role of Costal Cartilage

Costal cartilage plays a pivotal role in the thoracic cage by joining the ribs to the sternum.Functions of costal cartilage include:

• Providing flexibility to the rib cage, enabling expansion during breathing
• Contributing to the overall structure and stability of the chest
• Acting as cushioning to minimize impact trauma

Sternum Bone Anatomy

The sternum, an integral part of the human skeletal system, plays a crucial role in forming the rib cage and protecting internal organs. It consists of three main parts, which will be explored below.

Manubrium Structure

The manubrium is the uppermost section of the sternum, distinguished by its broad and trapezoid shape.Key characteristics of the manubrium include:

• It connects with the clavicles (collarbones) to stabilize the shoulder girdle.
• The top border of the manubrium is called the suprasternal notch, a visible dip between the neck and collarbones.
• Manubrium's lower edge articulates with the body of the sternum at the sternal angle, an important landmark in thoracic anatomy.

Body of Sternum Details

The body of the sternum, or gladiolus, is the longest part of the sternum, making up the central portion.Features of the body include:

• It serves as the attachment for the true ribs (ribs 2-7) through costal cartilages, forming the chest structure.
• The sternal angle, where it joins with the manubrium, marks the level of the second rib, facilitating the rib count process during medical procedures.
• The sternum's body is flattened, offering a stable surface for rib articulation and protection for thoracic organs.

Xiphoid Process Characteristics

The xiphoid process is the smallest and most variable part of the sternum, notable for its cartilaginous nature which ossifies with age.Noteworthy aspects of the xiphoid process include:

• At birth, it is predominantly cartilaginous and only ossifies completely after middle age.
• It acts as an attachment site for muscles of the anterior abdominal wall such as the diaphragm.
• The xiphoid process can be a landmark in cardiopulmonary resuscitation (CPR), highlighting the lower limit of chest compressions.

Sternum Anatomy Function

The sternum is central to the structure and function of the thoracic skeleton. Its primary functions involve protecting vital organs, assisting in respiration, and providing attachment points for muscles.

Importance in Respiratory System

The sternum plays a significant role in the respiratory system, particularly during the mechanics of breathing.When you inhale, your rib cage expands. The sternum moves slightly upwards and outwards, contributing to the increase in thoracic volume necessary for lung expansion.Important interactions include:

• Aid in Lung Expansion: By moving with the rib cage, the sternum ensures adequate space for lung inflation.
• Rib Articulation: The sternum provides an anchor for the first seven ribs, enabling thoracic expansion.
• Muscular Attachment: Provides attachment for muscles like the intercostals, which aid in the respiratory movement.

Protective Role of Sternum

The sternum is a crucial component for protection in the human body, forming the front part of the rib cage, sheltering vital organs from potential harm.Elements of its protective role include:

• Shielding Organs: It covers the heart and lungs, critical organs susceptible to damage from external impacts.
• Structural Support: Provides a firm base for the rib array, distributing any force across the chest.
• Impact Absorption: The rigid nature of the sternum helps in absorbing shocks, reducing the risk of injury to the organs it protects.