9 The Shoulder Complex

Question 1

What are the four joints of the shoulder?

Answer 1

• glenohumeral (GH)
• acromioclavicular (AC)
• sternoclavicular (SC)
• scapulothoracic (ST)

Question 2

Where is the only articulation between the upper limb and the trunk?

Answer 2

The SC joint

Question 3

What structures are in the subacromial space? Inflammation of what ligament might compress these?

Answer 3

• supraspinatus tendon
• biceps long head tendon
• subacromial bursa

inflammation of the coracoacromial ligament might compress these structures

Question 4

This labrum deepens the GH socket and improves articulation.

Answer 4

(fibrocartilagenous) Glenoid Labrum

Question 5

This forms a vault for the protection of the humeral head. If it thickens, it can contribute to impingement syndrome

Answer 5

coracoacromial ligament

Question 6

What kind of joint is the acromioclavicular?

Answer 6

synovial plane

Question 7

What kind of joint is the sternoclavicular?

Answer 7

triaxial saddle with a disk

Question 8

What nerves primarily innervate the shoulder complex?

Answer 8

• nerve roots C5-T1 (brachial plexus)
• supraclavicular nerves (C3-C4)

Question 9

What are the coracoclavicular ligaments?

Answer 9

conoid and trapezoid

Question 10

In which direction does the medial clavicle move relative to scapula during elevation/depression? During protraction/retraction?

Answer 10

• elevation/depression: opposite direction of scapula
• protraction/retraction: same direction as scapula

Question 11

When does the clavicle rotate?

Answer 11

Rotation of the clavicle occurs as an accessory motion with humeral elevation >90°. This cannot occur as an isolated, voluntary movement.

Question 12

Where does the Scapulothoracic joint reside?

Answer 12

(not a true jt) Typically resides between ribs 2 and 7, with the root of the scapula at rib 3.

Question 13

What direction of tipping occurs with normal scapular downward or upward rotation?

Answer 13

• upward rotation: posterior tipping
• downward rotation: anterior tipping

Question 14

Scapular retraction aka…

Answer 14

adduction

Question 15

Scapular protraction aka…

Answer 15

abduction

Question 16

When this ligement thickens, it can contribute to impingement syndrome of the shoulder

Answer 16

coracoclavicular ligament (tends to thicken due to repetitive trauma during overhead movements and excessive superior translation of humeral head)

Question 17

What direction does the SC joint move with GH flexion, scaption or abduction?

Answer 17

superiorly, anteriorly

Question 18

What direction does the AC joint move with GH flexion, scaption or abduction?

Answer 18

moves with scapula (superiorly with posterior rotation)

Question 19

What direction does the ST joint move with GH flexion, scaption or abduction?

Answer 19

upward rotation, protraction

(note that with GH flexion, at end range, the scap retracts and posteriorly tips)

Question 20

What direction does the SC joint move with GH extension?

Answer 20

inferiorly, posteriorly

Question 21

What direction does the AC joint move with GH extension?

Answer 21

moves with scapula (anteriorly and inferiorly)

Question 22

What direction does the ST joint move with GH extension?

Answer 22

downward rotation, retraction, anterior tipping

Question 23

This shoulder mm extends to the lumbar spine and can therefore cause excessive lordosis with overhead humeral movement if short.

Answer 23

latissimus dorsi

Question 24

Under the hook of the acromion and coracoacromial ligament reside several structures, including supraspinatus tendon and subacromial bursa. These structures are vulnerable to impingement due to several factors. These factors are:

Answer 24

• Acromial shape
• Weak external rotators
• Short internal rotators
• Weak scapular depressors

Question 25

What are the degrees of motion of the GH relative to the scapula with elevation of the humerus (flexion, scaption, abduction) througth various ROMs?

Answer 25

(GH:scap)

• 0-30° - 1:0 (movement is almost purely GH)
• 30°-120° - 1:1 (both move together)
• 120°-180° - 2:1

Question 26

If there is early or excessive movement of either the GH or scapula during flexion, scaption or abduction, what is likely happening at the other.

Answer 26

other joint is likely restricted

Question 27

What are things to look for when assessing the shoulder?

Answer 27

• scapular position (wing? tilt? protracted? rotation?)
• GH rotation
• T-spine position
• C-spine
• clavicle level
• pelvis and L-spine