DELTOID

ORIGIN

Anterior Part: Anterior border of the lateral third of the clavicle
Medial Part: Lateral border of the acromion process of the scapula
Posterior Part: Inferior edge of the scapular spine

INSERTION

Anterior Part: The deltoid tuberosity on the lateral surface of the proximal humeral shaft
Medial Part: The deltoid tuberosity on the lateral surface of the proximal humeral shaft
Posterior Part: The deltoid tuberosity on the lateral surface of the proximal humeral shaft

ACTION

Anterior fibers: Abduction, flexion, horizontal adduction, and internal rotation of the glenohumeral joint

Middle fibers: Abduction of the glenohumeral joint

Posterior fibers: Abduction, extension, horizontal abduction, and external rotation of the glenohumeral joint

INNERVATION

Interosseous branch of the median nerve (C8, T1)

PRIMARY JOINT

Glenohumeral Joint

KEY STRENGTH TRAINING EXERCISES

Standing dumbbell press

Prone reverse flye

NEW STRENGTH TRAINING EXERCISES