Label the Structures of the Pectoral Girdle and Surrounding Bones

Introducing Label the Structures of the Pectoral Girdle and Surrounding Bones, a comprehensive guide delving into the intricate skeletal framework that supports and protects vital organs within the human body. This article unravels the anatomy of the pectoral girdle, meticulously examining its components and their functional significance.

Our exploration begins with the pectoral girdle, a bony structure encasing the chest cavity. We’ll dissect its boundaries and constituent bones, including the clavicle, scapula, and sternum, highlighting their unique shapes, locations, and articulations. We’ll then venture beyond the pectoral girdle, identifying the surrounding bones and their pivotal role in stabilizing and supporting this vital structure.

Clavicle

The clavicle, commonly known as the collarbone, is a slender, elongated bone that forms the anterior portion of the pectoral girdle. It extends from the sternum medially to the acromion process of the scapula laterally. The clavicle is slightly S-shaped, with its medial end being thicker and broader than its lateral end.

Articulations

The clavicle articulates with three bones:

• Medially, it articulates with the manubrium of the sternum at the sternoclavicular joint.
• Laterally, it articulates with the acromion process of the scapula at the acromioclavicular joint.

Functions

The clavicle plays several crucial roles in the function of the pectoral girdle:

• It helps to keep the shoulder joint in place.
• It provides a point of attachment for the muscles of the shoulder and neck.
• It helps to protect the underlying blood vessels and nerves.
• It allows for a wide range of motion of the upper limb.

Scapula

The scapula, also known as the shoulder blade, is a flat, triangular bone located on the posterior aspect of the thoracic cage. It is approximately 15-20 cm in length and 10-15 cm in width, with a thickness of about 2-3 mm.

The scapula is positioned obliquely, with its superior angle directed medially and its inferior angle directed laterally.The scapula has three borders: the superior border, the medial border, and the lateral border. The superior border is the shortest and thinnest of the three borders.

The medial border is the longest and thickest of the three borders, and it is slightly concave. The lateral border is intermediate in length and thickness between the superior and medial borders.The scapula has three processes: the acromion process, the coracoid process, and the spine.

The acromion process is a flat, triangular projection located at the lateral end of the superior border. The coracoid process is a hook-like projection located at the lateral end of the medial border. The spine is a ridge that runs obliquely across the posterior surface of the scapula from the medial border to the lateral border.The

scapula has three notches: the suprascapular notch, the coracoid notch, and the inferior scapular notch. The suprascapular notch is located on the superior border of the scapula, just lateral to the spine. The coracoid notch is located on the lateral border of the scapula, just inferior to the coracoid process.

The inferior scapular notch is located on the lateral border of the scapula, just superior to the inferior angle.The scapula has two fossae: the supraspinous fossa and the infraspinous fossa. The supraspinous fossa is located on the posterior surface of the scapula, above the spine.

The infraspinous fossa is located on the posterior surface of the scapula, below the spine.The scapula articulates with the clavicle at the acromioclavicular joint and with the humerus at the glenohumeral joint.

Sternum

The sternum, also known as the breastbone, is a flat, elongated bone that forms the anterior portion of the thoracic cage. It is located in the midline of the chest and extends from the clavicles to the xiphoid process.

The sternum consists of three parts: the manubrium, the body, and the xiphoid process. The manubrium is the superior portion and articulates with the clavicles and the first costal cartilages. The body is the middle portion and articulates with the second to seventh costal cartilages.

The xiphoid process is the inferior portion and is a small, cartilaginous projection.

Articulations of the Sternum, Label The Structures Of The Pectoral Girdle And Surrounding Bones

• Clavicles
• First to seventh costal cartilages

Functions of the Sternum

• Protects the heart, lungs, and other mediastinal structures
• Provides attachment for the ribs and costal cartilages
• Provides a point of origin for the pectoralis major and sternocleidomastoid muscles

Ribs

The ribcage, formed by the ribs and sternum, provides protection to vital organs like the heart and lungs. The ribs are thin, curved, and flat bones that form the lateral walls of the thoracic cavity. They contribute to respiratory movements and provide attachment sites for muscles.

Types of Ribs

There are 12 pairs of ribs, classified into three types based on their attachments to the sternum:

• True ribs:The first seven pairs of ribs directly connect to the sternum through costal cartilages.
• False ribs:The 8th, 9th, and 10th pairs of ribs indirectly connect to the sternum via costal cartilages that join to the costal cartilage of the 7th rib.
• Floating ribs:The 11th and 12th pairs of ribs do not connect to the sternum or other ribs; they are free at their anterior ends.

Articulations

The ribs articulate with various bones:

• Vertebral column:Each rib articulates with two vertebrae, except for the 1st and 12th ribs, which articulate with one vertebra each.
• Sternum:The true ribs connect to the sternum through costal cartilages.
• Costal cartilages:The costal cartilages of the false ribs connect to the costal cartilage of the 7th rib.

Summary: Label The Structures Of The Pectoral Girdle And Surrounding Bones

In conclusion, the pectoral girdle and surrounding bones form an intricate skeletal network, providing a robust framework for the chest cavity and its vital contents. Each component plays a crucial role in protecting organs, facilitating movement, and ensuring overall structural integrity.

Understanding the anatomy of this region is essential for healthcare professionals, fitness enthusiasts, and anyone seeking a deeper comprehension of human anatomy.