Scapulothoracic joint

The scapulothoracic joint (also known as the scapulocostal 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.

Movement

The scapulothoracic joint allows for six distinct movements facilitated by the following muscles

• elevation: upper fibers of trapezius and levator scapulae
• depression:
  • passive: gravity (usually sufficient)
  • active: lower fibers of serratus anterior, and pectoralis minor
• protraction: upper and middle fibers of serratus anterior and pectoralis minor
• retraction: middle fibers of trapezius and rhomboids
• lateral rotation: upper fibers of trapezius and lower fibers of serratus anterior
• medial rotation:
  • passive: gravity with controlled relaxation of trapezius and serratus anterior
  • active: levator scapulae and rhomboids