The scapulothoracic joint is a not an anatomical joint as it does not refer to two opposing bones, but to a physiological joint of the pectoral girdle. The scapula is held against the thoracic wall by many muscles and the strut of the clavicle secondarily attaching it to the manubrium.
The scapulothoracic joint allows for the complex scapular movements in relation to the thoracic cage: elevation and depression, protraction and retraction, and medial and lateral rotation.
The scapulothoracic joint allows for six distinct movements facilitated by the following muscles
- elevation: upper fibres of trapezius and levator scapulae
- passive: gravity (usually sufficient)
- active: lower fibres of serratus anterior, and pectoralis minor
- protraction: upper and middle fibres of serratus anterior and pectoralis minor
- retraction: middle fibres of trapezius and rhomboids
- lateral rotation: upper fibres of trapezius and lower fibres of serratus anterior
- passive: gravity with controlled relaxation of trapezius and serratus anterior
- active: levator scapulae and rhomboids