The deltoid muscle is used in all side lifting movements and any movement of the humerus on the scapula. It is divided into two portions, anterior and posterior, with the fibres having different roles due to their orientation.


  • Outer 1/3 of the clavicle
  • Acromion process
  • Spine of the scapula


  • Deltoid tuberosity on the humerus


  • Anterior portion - Shoulder flexion and internal rotation
  • Posterior portion - Shoulder extension and external rotation
  • All fibres - Shoulder abduction

Shoulder Joint Muscles:


  • Axillary nerve

Daily uses

  • Lifting

How can I stretch it?

How can I strengthen it?

More Human Muscles: