Shoulder Function

Question 1

What is the main function of the shoulder girdle?

Answer 1

Connects upper limb to the axial skeleton.

Question 2

What are the joints of the shoulder girdle?

Answer 2

Sternoclavicular, acromiocalvicular, glenohumeral, scapulothoracic

Question 3

Sternoclavicular joint ligaments?

Answer 3

Interclavicular, costaclavicular, sternoclavicular

Question 4

What is the function of the interclavicular ligament?

Answer 4

Limits superior and lateral displacement between clavicles.

Question 5

What is the function of the costoclavicular ligament?

Answer 5

The main support that limits all ROM except depression. Connects inferior clavicle to 1st costal cartilage.

Question 6

What is the function of the sternoclavicular ligament?

Answer 6

Limits anterior and posterior glide/translation of the clavicle.`

Question 7

What are the main ligaments of the acromioclavicular joint?

Answer 7

Acromioclavicular ligament, coracoclavicular ligament.

Question 7

What is the function of the acromioclavicular ligament?

Answer 7

Limits superior motion. Prevents the clavicle from being driven under the acromion.

Question 8

What is the function of the coracoclavicular ligament?

Answer 8

Provides strength/stabilizes to the AC joint and provides means by which the scapula and limb can suspend from the clavicle. It creates a roof to prevent superior translation of the humerus and protects the bursa.

Question 9

What is the glenohumeral joint?

Answer 9

The articulation between the large head of the humerus and the shallow socket of the glenoid fossa. 25-30% sits in fossa.

Question 10

What does the glenoid labrum do?

Answer 10

Increases contact area with humeral head and therefore helps to stabilize. Deepens by 5-7mm for more space. Suctions head to the glenoid cavity.

Question 11

What are the glenohumeral ligaments?

Answer 11

Superior, middle, inferior, coracohumeral.

Question 12

What do the superior, middle and inferior glenohumeral ligaments do?

Answer 12

Tightens to prevent anterior displacement and external rotation to prevent dislocations.

Question 13

Humeral head position changes that can cause instability/injury are?

Answer 13

Muscle imbalances, instability, loss of neural control.

Question 14

What is the main direction that causes dislocations?

Answer 14

Anterior dislocation.

Question 15

Which rotators of the shoulder produce more force and why?

Answer 15

Internal rotators because there is an overall greater cross-sectional area of the internal rotators. More force= better for high-speed throwing.

Question 16

What is the function of the scapulothoracic joint?

Answer 16

Stability.

Question 17

What is the scapulohumeral Rhythm?

Answer 17

Shoulder abduction is 180 degrees because of 2:1 ratio between glenohumeral (2) and scapulothoracic joints (1).

Question 18

What can occur with a pinched nerve?

Answer 18

No signal to a muscle, muscle paralysis, head and scapula rotate anteriorly, dislocations and injury.

Question 19

Shoulder conditions

Answer 19

Instability, impingement or tendinopathy

Question 20

What is instability?

Answer 20

Glenoid labrum injury. Dislocation can occur and subluxation

Question 21

What is impingement or tendinopahty?

Answer 21

Scapular control (muscular imbalance, innervation)
Humeral head position (muscular imbalance)

Question 22

What can instability cause?

Answer 22

Anterior dislocation–most traumatic sports injury. The arm is forced into excessive abduction and external rotation.
Can cause damage to the glenoid labrum’s attachment to anterior glenoid margin
Ligament damage
Damage to axillary nerve (impaired sensation on lateral side of arm. impairment of teres minor and deltoid)

Question 23

What occurs during a labral tear?

Answer 23

Less stability after recovery because it serves as an attachment site for shoulder capsule, glenohumeral ligament and biceps tendon

Question 24

What occurs during impingement?

Answer 24

Poor scapular control when performing arm movements–>causes inadequate movement of scapula. Inadequte movement of the scapula causes tendinopathy.

Question 25

What is tendinopathy?

Answer 25

Small tears in ligaments or muscles that cause pain.

Question 26

What occurs during innervation of long thoracic nerve?

Answer 26

Blunt trauma causes winging. Causes paralysis of serratus anterior.