Origin: Lateral anterior 1/3 of the clavicle, coracoid process of the acromion, scapula spine
Insertion: the deltoid tuberosity on the lateral surface of the humerus
Actions: The main action of the deltoid is to abduct the humerus (an action initiated with supraspinatus). The clavicular portion adducts the humerus towards the midline and medially rotates the humerus to aid flexion of the humerus by pectoralis major. The spinous portion aids extension of the humerus by latissimus dorsi by laterally rotating the humerus.
Nerve supply: the axillary nerve C5, C6
Pronunciation: dehl-toyed