What makes up the shoulder girdle and the shoulder joint?

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The shoulder girdle, also known as the pectoral girdle, connects your arms to the bones and muscles along the axis of your body. You have two shoulder girdles that are responsible for supporting the shoulder regions on both sides of your body and enabling movement.

Your shoulder girdle is made up of two bones: your collarbone (clavicle) and your shoulder blade (scapula).

Clavicle bone

Your clavicle an S-shaped bone. It is situated at the front of your body in a horizontal position. It helps to protect the nerves and blood vessels that pass between your trunk and arms. It is the only direct connection between your shoulder girdle and axial skeleton.

The clavicle bone consists of three sections:

  1. Medial end

The medial end is triangular. It attaches to the sternum, forming the sternoclavicular joint.

  1. Lateral end

The lateral end is a flat piece that connects to the scapula. It forms the acromioclavicular joint.

  1. Shaft

The shaft is the body of the clavicle, which connects the lateral and medial end.

Scapula bone

The scapula is a triangular bone situated at the back of your shoulder. It connects your humerus (upper arm) with your clavicle. It is also an attachment point for various muscles in your shoulder, upper arm, neck and back.

Your scapula consists of three borders:

  1. Medial border

The medial border, also known as the vertebral border, runs parallel to the thoracic vertebrae (12 bones that make up the upper part of your spine).

  1. Lateral border

The lateral border is also known as the axillary border.

  1. Superior border

The superior border is the thinnest as well as the shortest of the three borders. The scapula also has two angles: the lateral angle and the inferior angle.

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Shoulder joints

Your shoulder joint consists of four main joints:

  1. Sternoclavicular joint

The sternoclavicular joint is where your clavicle and sternum meet. It allows your clavicle to move in three different planes.

  1. Scapulothoracic joint

The scapulothoracic joint, or scapulocostal joint, is where the scapula bone meets the ribs at the back of your chest. It relies on the muscles, which surround it, for control.

  1. Acromioclavicular joint

Your clavicle and acromion of the scapula come together at the acromioclavicular joint. It also enables movement in three planes.

  1. Glenohumeral joint

The glenohumeral joint, or shoulder joint, is the ball-and-socket connection between the humerus and scapula.

When we think about how the arm and shoulder are connected, this is usually the joint we picture.

Your shoulder girdle is the most agile and also the most vulnerable joint in the body. You have two of these joints. It is made up of the clavicle and scapula bones and four joints: sternoclavicular joint, scapulothoracic joint, acromioclavicular joint and glenohumeral joint. This series of bones and joints is responsible for connecting your arm and shoulder. It enables you to move your arm.

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