The deltoid muscle is a large muscle that encompasses the shoulder joint. The deltoid is divided into three different portions, or heads:
- The anterior deltoid is located at the front of the shoulder.
- The posterior deltoid is located at the back of the shoulder.
- The lateral deltoid is sandwiched between the anterior and posterior deltoids.
Its major action is to abduct the arm (lift the arm out to the side of the body) as well as assist in forward elevation (lifting the arm out in front of the body).
The deltoid is a very powerful muscle and is needed for all types of athletic endeavors.
