shoulder complex

Question 1

4 key points

Answer 1

1. The primary function of the shoulder complex is to position the upper extremity in space
2. The shoulder complex achieves a wide range of movement
3. Movement of the upper limb on the trunk requires the coordinated interaction of the 3 joints of the shoulder complex
4. This increased mobility exposes the shoulder complex to the risk of injury

Question 2

shoulder region

Answer 2

Osteology:
Clavicle
Scapula
Proximal humerus Sternum
Thoracic cage

Question 3

shoulder region Arthrology:

Answer 3

Sternoclavicular joint (SCJ) 
Acromioclavicular joint (ACJ) 
Glenohumeral joint

Question 4

clavicle structure

Answer 4

• Horizontal alignment
• S-shape
• Sternal end (thick)
• Acromial end (flattened)
• Inferior surface markings for ligaments
• Costal tuberosity
• Conoid tubercle
• Trapezoid line
long bone
* site of attachment between appendicular and axial skeletons

Question 5

clavicle functions

Answer 5

1. Muscle attachment
2. Protect neurovascular bundle
3. Strut (framework)
4. Transmit force UL to axial
5. Increase ROM of shoulder complex

Question 6

scap functions

Answer 6

Muscle attachment

Transmit force

Question 7

Clavicle Scapular position

Answer 7

Scapulae not connected posteriorly
The position of the scapula is affected by the shape of the thoracic cage
Plane of scapula = 30 – 450 from the frontal plane

Question 8

translations of scap

Answer 8

elevation
depression
abduction
adduction

Question 9

rotations of the scap

Answer 9

anterior tilt
posterior tilt
upward rotat.
downward rotation
internal rotat.
external rotat.

Question 10

humerus function

Answer 10

Muscle attachment
• Force transfer
• Length / lever

Question 11

humerus structure

Answer 11

Head – medially, superiorly & posteriorly
• Anatomical neck
• Greater & lesser tubercles
• Intertubercular (bicipital) sulcus / groove
• Surgical neck
• Deltoid tuberosity

Question 12

clavicle s shape

Answer 12

permits the upward rotation of the clavicle

to accommodate scapular upward rotation with minimal movement required at the SC & AC joints

Question 13

clavicle fractures

Answer 13

mid 1/3 shaft

Fractures of the clavicle and ACJ dislocations (often with coracoid avulsion #’s) are more common than SCJ dislocations!

Question 14

Head of humerus faces in GHJ

Answer 14

– medially
– superiorly
– posteriorly

Question 15

movements of scap.

Answer 15

– Translations:
» Elevation – depression
» Abduction (Protraction) – Adduction (retraction)
– Rotations:
» Upward – downward rotation » anterior tilt – posterior tilt
» Internal – external rotation

Question 16

clavicle curvatures

Answer 16

medial 2/3 convex anteriorly

lateral 1/3 convex posteriorly