Shoulder Flashcards
Acromion process
end of the top of the scapular
Coracoid process
small hook-like structure at the top front part of the scapula
Glenoid
the socket of the Glenohumeral joint
humeral head
is the ball of the Glenohumeral joint
Clavicle
collarbone
Scapula
shoulder blade
What makes up the shoulder joint?
- Glenohumeral joint - AC joint (acromioclavicular)
What is the Glenohumeral joint
– ball and socket joint between the scapula and the humerus o Glenoid is the socket, humeral head is the ball o Yoga poses can contribute to injury – anything that adds weight
What is the AC joint (acromioclavicular)?
Junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle
What is the Coracohumeral ligament
- joins coracoid process to the humerus - helps extend and move back, stops arm from falling
What is the Glenohumeral ligament?
stabilisation of the glenohumeral joint in adduction and external rotation all the way around the socket and ball
What is the Coracoacromial ligament?
connects the acromion and coracoid process of the scapula, allows complex shoulder movement without separation of the scapula from the clavicle
What do muscles do?
Move the bones
How are muscles attached to bones?
With tendons
What is the rotator cuff
- Rotator cuff is a group of muscles and tendons that create a cuff around the shoulder joint - Allow movement of the arm - Keeps humeral head in the shoulder socket (glenoid)
What is a pre-requisite for the rotator cuff?
- To be part of the shoulder girdle – attached to scapular and the humeral head
Muscles of the rotator cuff?
- Four muscles – SITS o Supraspinatus (on the top o Infraspinatus – back of scapular o Teres minor o Subscapularis – inside the front of the scapular, sits almost touching the ribs
What are the deltoids?
Anterior, lateral, posterior
What does the front deltoid do?
contracts pull shoulder forward and internally rotate
What does the deltoid medial do?
central deltoid – lifts arm up
What does the rear deltoid do?
draws shoulder back and externally rotates (with help of infraspinatus)
What limits the range of movement for arms over head?
- AC joint limits the range of movement for arms over head - nice modification take the arms forward so don’t get the compression in our arms bone when lift upward
What is the teres major and why isn’t it part of the rotator cuff?
- From the scapula to the humeral shaft - not part of the rotator cuff as it does not insert into the humeral head
What does the teres major do?
- internally rotates the arm bone - Pulls shoulders forward - adducts the arm - extends the arm forward at shoulder - close relationship with latissimus dorsi
What is the teres minor?
- Works with the infraspinatus - pulls shoulders back - Pulls the arm toward the body (i.e. from above the body back to the side of the body) - extension of the shoulder (means moving it posteriorly)
What does the Supraspinatus do?
o Supraspinatus (on the top) – holds head of arm bone in the shoulder socket, abducts arm bone, takes out to side and initiates the lift of your arm (deltoid then lifts the arm up)
Poses – W1, chair, Tadasana, bottom arm in Gomukhasana
What does the infraspinatus do?
– back of scapular; when it contracts it externally rotates the shoulder head back
What does the teres minor do?
pulls arm bone back in (adduction), subtly turns out
What does the Subscapularis do?
o Subscapularis – inside the front of the scapular, sits almost touching the ribs – internally rotates your arm bone Poses – Reverse prayer, ½ binds
Arms in gomukhasana?
o “down” arm moves into full shoulder internal rotation with extension (extension means moving it posteriorly). Limited rotation due to infraspinatus, supraspinatus and deltoids. Big guys won’t be able to do this very well o “up” arm moves into full shoulder flexion (anywhere from resting position beside legs to above head) with external rotation and full elbow flexion. Teres major, subscapularis, lats, triceps - if tight will limit the external rotation
External rotation of the shoulder muscles?
Infraspinatus + Teres Minor: External Rotation - responsible for external rotation of the arm bone (turning the arm out) - can be felt as a slight contraction on the backside of the shoulder blade - postures lifting arm overhead, externally rotating the arm to lift - infraspinatus and teres minor work together - poses o raised arms, extended side angle, downward dog o Handstand, Top arm in Gomukhasana
Stabilising muscles of the shoulder blade
- Shoulder blades must be stabilised in weight-bearing exercises
- The two muscles that negotiate the placement of each scapula on the back are the serratus anterior and the rhomboid. Both muscles insert on the inner edge (or medial border) of the shoulder blade and have opposing actions. When these muscles are equally turned on, they work together to stabilize the shoulder blade on the back.
Scapular protraction v retraction
o Scapular retraction refers to moving the shoulder blades (scapula) towards the spine.
o Scapular protraction – moving the shoulder blades away from the spine. If you give yourself a big bear hug your shoulder blades will protract.
Serratus anterior – scapula protraction
o Protracts scapula – pulling of the scapular forward and towards the rib cage away from the spine
o Rounding the back in cat pose
o Pushing the floor away from you or lift up out of your shoulders – it is the serratus anterior abducting the scapula which allows you to do this
Rhomboid – scapula retraction
o Retracts scapula – pulls scapula onto the back toward the spine, expands the chest o Arching your back in cow pose, dropping chest toward the floor
shoulder blade
Scapula
collarbone
Clavicle
How many shoulder joints?
2
What are the shoulder joints
- Glenohumeral joint – ball and socket joint between the scapula and the humerus o Glenoid is the socket, humeral head is the ball
- AC joint (acromioclavicular) – junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle.
What do the shoulder joints allow us to do?
Together the two joints allow us to raise, lower, and rotate our arm bones as well as to move the shoulder blades on and off the back.
Ligaments of the shoulder
- Ligaments join bone to bone and limit movement
- Coracohumeral ligament – joins coracoid process to the humerus - helps extend and move back, stops arm from falling
- Glenohumeral ligament – stabilisation of the glenohumeral joint in adduction and external rotation all the way around the socket and ball
- Coracoacromial ligament - connects the acromion and coracoid process of the scapula, allows complex shoulder movement without separation of the scapula from the clavicle
Muscles of the shoulder – the rotator cuff
- Muscles move the bones – tendons attach muscles to bone - white parts in the picture are tendons – insertion on the humeral head
- Rotator cuff is a group of muscles and tendons that create a cuff around the shoulder joint
- Allow movement of the arm
- Keeps humeral head in the shoulder socket (glenoid)
- Harming them – wear and tear, not engaging them properly
What muscles are part of the shoulder girdle?
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
Teres minor v teres major
Teres minor
- Works with the infraspinatus
- pulls shoulders back
- Pulls the arm toward the body (i.e. from above the body back to the side of the body)
- extension of the shoulder (means moving it posteriorly)
Teres major
- From the scapula to the humeral shaft
- not part of the rotator cuff as it does not insert into the humeral head
- internally rotates the arm bone
- Pulls shoulders forward
- adducts the arm
- extends the arm forward at shoulder
- close relationship with latissimus dorsi
Bones of the shoulder
What are the muscles of the rotator cuff?
Supraspinatus Infraspinatus Teres minor Subscapularis
What does the supraspinatus muscle do?
Abducts the arm
What does the infraspinatus muscle do?
Externally rotates the arm
What does teres minor muscle do?
Externally rotates the arm
What does the subscapularis muscle do?
Internally rotates the humerus
Which muscle is highlighted in purple?
Subscapularis
Which muscle is highlighted in blue?
Infraspinatus
Which muscle is highlighted in yellow?
Teres minor
Which muscle is highlighted in green?
Supraspinatus
Infraspinatus and teres minor - example
If you stand in Tadasana, palms facing your body, and then turn your elbow creases forward (the palms will naturally turn forward too), you’ve externally rotated your shoulder–and you’ve just used the infraspinatus and teres minor.
