- Shoulder (Side)
- Side Delts
- Lateral Deltoid (1 of 3 Deltoids)
- Acromion (Lateral)
- Humerus (Lateral)
- Deltoid Tuberosity
The lateral deltoid is involved in shoulder abduction when the shoulder is internally rotated. It is involved in shoulder flexion when the shoulder is internally rotated. It is involved in shoulder transverse abduction (shoulder externally rotated) but is not utilized significantly during strict transverse extension (shoulder internally rotated).
Due to increasing moment arm with abduction, lateral deltoid is more effective at shoulder abductor in higher abduction angles in contrast to supraspinatus which is more effective shoulder abductor at lower abduction angles.