Deltoid (Posterior)

Other Names

• Shoulder (Rear)
• Rear Delts

Heads

• Posterior Deltoid (1 of 3 Deltoids)

Also see

• Anterior Deltoid
• Lateral Deltoid

Movement

Shoulder

• Extension
• Transverse Extension
• Transverse Abduction
• External Rotation

Attachments

Origin

• Scapula
  • Spine (Inferior edge)

Insertion

• Humerus (Lateral)
  • Deltoid Tuberosity

Comments

The posterior deltoid is a stronger transverse extensor (shoulder internally rotated) than transverse abductor (shoulder externally rotated). It is strongly involved in transverse extension, particularly since the latissimus dorsi is very weak in strict transverse extension. The posterior deltoid is the primary shoulder hyperextensor, since the pectoralis major nor the latissimus dorsi does not extend the shoulder beyond anatomical position (aka hyperextension)