The pectoral girdle anchors the upper limb to the trunk.
The only boney stability of the upper limb to the trunk is through the connection between the clavicle and the sternum.
The remaining stability of the shoulder complex depends on muscles.
As a result, the shoulder complex has a wide range of motion.
Instructional Video
Scapular Support
The combined joints connecting the scapula,clavicle and humerus (glenohumeral joint) form the shoulder complex and anchor the upper limb to the trunk.
The only boney stability of the upper limb to the trunk is through the connection between the clavicle and the sternum.
The remaining stability of the shoulder complex depends on muscles, and as a result, the shoulder complex has a wide range of motion.

A. Superior view of the scapulothoracic joint. B. Scapular actions. C, D. Glenohumeral joint actions.
- Scapulothoracic joint. Formed by the articulation of the scapula with the thoracic wall through the scapular muscles, including the trapezius and the serratus anterior muscles. The scapulothoracic joint is not considered a true anatomic joint; as such, it is frequently referred to as a “pseudo joint” because it does not contain the typical joint characteristics (e.g., synovial fluid and cartilage).
- Acromioclavicular joint. A synovial joint formed by the articulations of the scapula (acromion) and the clavicle.
- Sternoclavicular joint. A synovial joint formed by the articulations between the clavicle and sternum.