The Deltoid is the uppermost shoulder muscle that is in the shape of a delta. It is made up of three parts that connect the scapula (shoulder blade), the top of the shoulder, and the clavicle (collarbone) to the humerus bone (upper arm). The three sections are called the Posterior, Middle, and Anterior, respectively. Collectively, the three sections of this powerful muscle allow you to move your arms and shoulders in a wide range of directions:
The Anterior Deltoid
- pulls the arm forward and up (such as doing an underhand toss)
- pulls it across your body (reaching across your chest to the opposite shoulder)
- medially/laterally rotates the shoulder joint in towards the front of the body
- assists in lifting the arm overhead from the side (snow angle upward movement)
The Middle Deltoid
- pulls the arm away from the side of the body
- lifts the arm overhead from the side (the upward arm movement of a jumping jack)
The Posterior Deltoid
- pulls the arm back and up, extending the arm behind the hips (the starting windup for underhand toss or bowling)
- externally rotates the shoulder joint out toward the back (like a backswing in tennis)
- assists in lifting the arm overhead from the side.
It is very important to not rush the recovery process. Depending on the severity of the injury, the Deltoid could feel better in several days or it may take months. Once any swelling and pain have gone away, start slowly using the shoulder more with gentle movements, stretching the Deltoids, and keep any lifting minimal and light. After full range of motion is back with no pain or discomfort, you can start to go back to your normal routines. Do keep in mind that if you start to feel any pain or fatigue in your Deltoids during any activity, stop the activity and continue to rest the shoulder. Rushing your recovery will only set you back for a much longer time, and possibly a more severe injury to the Deltoid. I speak from experience on rushing a Deltoid injury. Be patient, listen to your body, set aside your ego, rest, and go easy on yourself. Your body will thank you.