The deltoids move the upper arm up and away from a neutral position at the side. They each have three different major regions, each with different attachment points around the shoulders. Each of these regions moves the arm in a different direction when flexed.
The deltoid muscle, located on the outside of the shoulder, helps rotate the upper arm and extend the arm at the shoulder. The deltoid has three different sets of fibers that help perform specific tasks.
Deltoid muscles, situated in the shoulders, are responsible for the majority of arm movements, including arm abduction, arm flexion and medial rotation, and arm extension and lateral rotation. These movements involve the deltoids working with the rotator cuff muscles, s...
Inner Body says that the three parts of the deltoid muscle are the anterior fibers, lateral fibers and posterior fibers. Each band of fibers originates from a separate location.
The deltoid is opposed by the pectoralis major and the latissimus dorsi when the arm is moved away from the body to the side. The deltoid group functions to stabilize the shoulder during rotation, preventing dislocation and allowing safe carrying of heavy objects.
While severe injuries to the shoulder joint often require physical therapy or surgery, minor injuries to the deltoid muscle respond to a routine involving rest, ice, compression and elevation. If these steps do not bring relief or if the injury causes severe pain and sw...
A variety of exercises that do not involve weights can be performed to strengthen the deltoids, such as Supermans and handstand push-ups. While these exercises are effective, the use of free weights can add more to a workout once body weight resistance is mastered.