Self-Directed Study, Requirement #2
By: Marcy Kerr-Lemus
There are four joints that comprise the shoulder. The joints are listed below starting from the medial and anterior part of the body and working outward through the shoulder.
Sternoclavicular
The sternoclavicular joint connects the medial end of the clavicle with the sternum. It connects the humerus and scapula to the torso. The movements of the SC joint include elevation. depression, protraction, retraction, and rotation. This joint does not touch the scapula but is guided by the movements of the scapula. (Varacallo, 2021)
To understand these movements, hold a pencil along your clavicle, with the eraser at your sternum and the tip at your shoulder.
Elevation
The eraser moves down towards your belly button and the tip moves up towards your ear.
Depression
The eraser moves up towards your nose and the tip moves down your hip.
Protraction
The whole pencil moves forward off your body slightly.
Retraction
The whole pencil pushes into your body.
Rotation
The pencil spins in place.
Acromioclavicular
The acromioclavicular joint connects the lateral end of the clavicle to the acromion process of the scapula. The movements of the AC joint include upward and downward tilting, posterior and anterior tilting, and internal and external rotation of the scapula. (Acriomioclavicular Joint, n.d.)
To learn these movements. Imagine you have big football shoulder pads on.
Upward rotation
The pad lifts up coming closer to your ear.
Downward rotation
The pad starts to slide off the end of your shoulder.
Internal rotation
The front side of the pad comes closer to your chin.
External rotation
The back side of the pad comes closer to your spine.
Anterior tilt
The front part of the pad starts to fall over your chest.
Posterior tilt
The back part of the pad starts to fall over your back.
Glenohumeral
The glenohumeral joint connects head of the humerus to the glenoid fossa of the scapula. In simple terms, it connects your arm bone to your shoulder blade. It has seven movements including extension, flexion, abduction, adduction, internal rotation, external rotation, and circumduction. (Glenohumeral Joint, n.d.)
Let’s learn the movements with some yummy ice cream! Make a fist with your right hand and imagine it is a scoop of vanilla ice cream. Hold your left hand open with the palm facing your of ice cream. We have 5 areas of the cone: top, front, back, inside, and outside. We are going to add toppings to your ice cream cone to learn the movements of the humeral head. (Kopelovich, n.d.)
Flexion
Spins posterior
Let’s put chocolate sauce on the inside of the ice cream cone. Take your ice cream come and put it directly into the palm of your left hand and spin it towards your L thumb to coat it in chocolate sauce.
Extension
Spins anterior
Now add a second layer of chocolate by spinning towards your L pinky.
Abduction
Rolls superior, glides inferior
Now, we want to put chocolate sauce on the top of the ice cream cone. Turn the top of the cone into your fingers on the L palm, and then push the cone down to the base of your palm.
Adduction
Rolls inferior, glides superior
We have too much sauce now! Remove the top of the ice cream cone and push the cone up the palm to remove the excess.
Internal rotation
Rolls anterior, glides posterior
Let’s add some sauce to the back of the cone. Rotate pinky to pinky and then push the cone towards the L thumb.
External rotation
Rolls posterior, glides anterior
Let’s add sauce to the front of the cone. Rotate thumb to thumb and then push the ice cream come back towards the L pinky.
Scapulothoracic
Finally, the fourth joint is the scapulothoracic joint. This is the articulation between the anterior side of the scapula and the thorax. It has ten movements including elevation, depression, protraction, retraction, upward and downward rotation, internal and external rotation, and anterior and posterior tilting. (Physio-pedia, n.d.)
To learn these motions, pretend you have butterfly wings on your back.
Elevation
Lift your wings just slightly so the crest of the wing shows above your shoulders.
Depression
Attempt to hide the wings so none of it shows above your shoulders.
Protraction
Wrap your wings around you as if you were a bat going to sleep.
Retraction
Open your wings as if they were a coat you needed to take off.
Upward rotation
Normally, the bottom point of the wing is pointing directly to your toes. Lift your wings to the side until that tip points the floorboard in your room, where the floor meets the wall.
Downward rotation
Now rotate that wing tip to point to the back of your shoes again.
Internal rotation
Take your wings off your body and stack them perpendicular to your body so the outside of the wing connects to your back.
External rotation
Take your wings off your body and stack them perpendicular to your body so the inside of the wing connects to your back.
Anterior tilting
Press the top of the wing into your upper back and lift the bottom of the wing off your body.
Posterior tilting
Press the bottom of the wing into your lower body and try to lift the top of the wing off your back.
These joints work together to create all the movements we love on the pole. When one joint moves, it automatically makes a shift at another joint. We move in many ways on the pole, but let’s look at four: vertical pulling, vertical pushing, horizontal pulling, and horizontal pushing.
Using the imagery from above combined with an isometric wall hold, we can see what each joint should be doing.
Action:
Sternoclavicular joint: pencil
Acromioclavicular joint: shoulder pad
Glenohumeral joint: ice cream cone
Scapulothoracic joint: wings
Horizontal pulling: sit in front of a doorway. Place your palm around the frame, in a thumb up position at shoulder height. Try to pull the frame to your body, without flexing the elbow.
The pencil moves closer to your body, as if it were going to connect with your upper ribs.
The back of the shoulder pad moves toward your spine and starts to slide off towards your back.
Put sauce on the front of the cone.
Hide the wings behind you, below your shoulders, and tip into your upper back.
Horizontal pushing: sit in front of a wall. Place your palm flat on the wall in a fingers up position and try to push the wall away from you.
The pencil moves off of the body, away from the ribs, like it was going to pop through your skin.
The front of the shoulder pad moves toward your nose and starts to slide off towards your chest.
Put chocolate sauce on the back of the cone.
The wings are wrapping around your side like a bat curling up, lifting high above your shoulders, and tipping down towards your legs.
Vertical pulling: lay on your back in front of a doorframe. Raise one arm to wrap your hand around the frame with thumb pointing into the ground.
Eraser at the sternum is lifting towards your chin while the tip at the shoulder is coming down towards your belly.
The pad slides towards the edge of your shoulder.
Take sauce off the top of the con.
The bottom of the wings are coming towards each other and dropping below the shoulders.
Vertical pushing:
Eraser at the sternum is moving towards your belly while the tip at the shoulder is moving closer to your ear.
The pad lifts towards your ear.
Push sauce on the top of the cone.
The top of the wings are coming towards each other, and becoming visible above the shoulders.
Bibliography
Acriomioclavicular Joint. (n.d.). Retrieved from Physio-pedia: https://www.physio-pedia.com/Acromioclavicular_Joint
Glenohumeral Joint. (n.d.). Retrieved from Physio-pedia: https://www.physio-pedia.com/Glenohumeral_Joint?utm_source=physiopedia&utm_medium=search&utm_campaign=ongoing_internal
https://www.physio-pedia.com/Glenohumeral_Joint?utm_source=physiopedia&utm_medium=search&utm_campaign=ongoing_internal. (n.d.). Retrieved from Physio-pedia: https://www.physio-pedia.com/Glenohumeral_Joint?utm_source=physiopedia&utm_medium=search&utm_campaign=ongoing_internal
Kopelovich, A. (n.d.). Shoulder Kinesiology: Glenohumeral Joint. Retrieved from https://www.youtube.com/watch?v=X4ozqdbAp-E
Physio-pedia. (n.d.). Retrieved from Scapulothoracic Joint: https://www.physio-pedia.com/Scapulothoracic_Joint
Varacallo, T. N. (2021, July 26). Anatomy, Shoulder and Upper Limb, Sternoclavicular Joint. Retrieved from National Library of Medicine: https://www.ncbi.nlm.nih.gov/books/NBK537258/