Pectoral Girdle, Anatomy, Functions, Muscles and Bones

Pectoral Girdle: The pectoral girdle, also known as the shoulder girdle, is a crucial component of the appendicular skeleton. It serves to connect the upper limbs to the axial skeleton. The human skeleton is divided into two main sections: the axial skeleton, which comprises 80 bones including the skull, vertebral column, ribs, and sternum, and the appendicular skeleton, which comprises 126 bones, including the pectoral girdle, pelvic girdle, and limbs.

Pectoral Girdle Bones

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Anatomy of Pectoral Girdle

Clavicle:

1. Medial end: This part of the clavicle connects to the sternum. It is triangular and forms the sternoclavicular joint.
2. Lateral end: This part of the clavicle connects to the scapula. Known as the acromial end, it is flat and forms the acromioclavicular joint.
3. Shaft: This is the main body of the clavicle.

Okazaki Fragments

Scapula:

1. Medial border (vertebral border): This border runs parallel to the thoracic vertebrae.
2. Lateral border (axillary border).
3. Superior border: This is the thinnest and shortest of the three borders.

1. Lateral angle.
2. Inferior angle.

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Pectoral Girdle Functions

• Flexion (forward bending)
• Extension (backward bending)
• Abduction (lifting sideways)
• Adduction (lowering sideways)
• Medial rotation (inward turning)
• Lateral rotation (outward turning)

• Pectoralis major and minor: chest muscles involved in arm flexion, adduction, and medial rotation.
• Latissimus dorsi: a large back muscle aiding in arm extension and adduction.
• Trapezius: an upper back muscle assisting in scapular movement and arm upward rotation.
• Deltoid: a major shoulder muscle responsible for arm abduction.
• Rotator cuff muscles: a group of muscles stabilizing the shoulder joint and enabling rotational movements.

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Pectoral Girdle Muscles, Tendons, and Ligaments