Origin/Insertion of Muscles - Shoulder - Deltoid (Posterior Head)

Deltoid (Posterior Head)
Origin: (Proximal Attachment) Spine of Scapula
Insertion: Deltoid Tuberosity of the humerus
Action: Laterally rotates the arm at the shoulder (glenohumeral) joint. Extends the arm at the shoulder joint

Spine of Scapula

Deltoid Tuberosity

Origin/Insertion of Muscles - Shoulder - Deltoid (Anterior and Middle Heads)

Deltoid (Anterior and Middle Heads)
Origin: Proximal attachments
            a) Anterior head: anterior surface of lateral clavicle
            b) Middle head: acromion process and spine of the scapula
Insertion: Deltoid tuberosity of the humerus
Action: Anterior Head: Flexes the arm at the shoulder; Medially rotates the arm at the shoulder
             Middle Head: Abducts the arm at the shoulder

Anterior Surface; Lateral Clavicle



Acromion Process; Spine of Scapula



Deltoid Tuberosity