In Part 1 of my shoulder series, which you can find HERE, I talked about the bones and joints of the shoulder girdle. Today I’ll be going over the movements and the muscles of the shoulder girdle. So, let’s get to it!
When identifying movements of the shoulder girdle, it helps to focus on a bony landmark of the scapula. The inferior angle of the scapula, the glenoid fossa, or the acromion process are all acceptable options. Movements of the shoulder girdle are pretty much movements of the scapula, with the sternoclavicular (SC) joint serving as a pivot point. As the scapula moves, watch where your bony landmark moves, and that will help you determine what shoulder girdle movement is being performed.
Primary Movements of the Shoulder Girdle
Abduction (Protraction) – Lateral movement of the scapula away from the spinal column. Protraction occurs at the top part of a pushup, in scapular pushups, and in forearm wall slides when moving your forearms to the wall.
Adduction (Retraction) – Medial movement of the scapula toward the spinal column. Whenever you pinch your shoulder blades together, you are adducting, or retracting, your scapulae. This also occurs in the forearm wall slide.
Elevation – Superior movement of the scapula. When you shrug your shoulders, you are elevating your scapulae.
Depression – Inferior movement of the scapula. Depression of the scapulae is optimal in many strength exercises and mobility exercises in the gym. In deadlifting and in the no money drill, the scapulae stay depressed at all times.
Upward Rotation – Turning the glenoid fossa upward coupled with superior and lateral movement of the inferior angle of the scapula away from the spinal column. This happens when simply raising your arm out to the side, as well as in scapular wall slides.
Downward Rotation – Returning the glenoid fossa to its normal position accompanied by medial and inferior movement of the inferior angle of the scapula toward the spinal column. Bringing your arm down to your side and scapular wall slides both involve downward rotation.
As the above title suggested, these are the primary movements of the shoulder girdle. There are other movements where the scapula must rotate or tilt on its axis, but for now, we’ll keep things simple and leave those on the backburner for another time.
Muscles of the Shoulder Girdle
There are 5 muscles primarily involved in movements of the shoulder girdle. All of these muscles originate on the axial skeleton (the skull, spinal vertebrae, or ribs to be exact) and insert on the scapula and/or the clavicle. These muscles play a very important role in dynamic stabilization of the scapula as well as in posture. For the sake of brevity, I’ll give a brief description of where the muscle is located and the movements that it causes.
The trapezius is located posteriorly in relation to the trunk. This muscle is divided into 3 parts: the upper fibers, middle fibers, and lower fibers. The upper fibers are involved in elevation, upward rotation, and extension and rotation of the head. The middle fibers retract and upwardly rotate the scapula. The lower fibers perform retraction, upward rotation, and depression.
The rhomboids (referred to as rhomboideus in the picture above) are located posteriorly to the trunk as well. There are 2 rhomboid muscles: rhomboid major and rhomboid minor. Rhomboid minor is superior to rhomboid major and smaller, but both are located deep (below) to the trapezius. Both rhomboid muscles perform the same functions, which are retraction, elevation, and downward rotation.
The pectoralis minor is located anteriorly to the trunk. It is deep to the pectoralis major and it protracts, depresses, and downwardly rotates the scapula. It is important to note that the pectoralis minor is the only muscle that can both depress and downwardly rotate the scapula.
I know this was a long post, so take a deep breath because you made it all the way through! Thank you for reading and hopefully you’ve increased your knowledge of the shoulder girdle!