11.1 Osteology and Arthrology of the Pectoral Girdle and Shoulder

Question 1

What is the coracoid process of the scapula? What does “coracoid” mean?

Answer 1

• The process that passes anteriorly under the scapula
• Coracoid means raven; process is shaped liked raven’s beak

Question 2

What is the equivalent structure to the acetabulum at the shoulder joint? What does it’s name mean?

Answer 2

• Glenoid fossa
• Comes from Greek Glene = “socket”; makes sense

Question 3

What type of joints are the acromioclavicular and sternoclavicular joints? What kind of cartilage lines them?

Answer 3

• They are synovial joints
• Lined by fibrocartilage

Question 4

Which ribs does the scapula overly?

Answer 4

2-7

Question 5

What is the function of the pectoral girdle?

Answer 5

To connect the upper limbs to the rest of the body

Question 6

What are the names of the two bony landmarks directly inferior and superior to the glenoid fossa? What muscle attaches to each?

Answer 6

• Supraglenoid and infraglenoid tubercle
• Supra: biceps brachii (long head)
• Infra: triceps brachii (long head)

Question 7

What is the structural classification of the acromioclavicular joint?

Answer 7

Diarthrodal

Question 8

What two ligaments stabilise the acromioclavicular joint?

Answer 8

• Coracoclavicular
• Coracoacromial

Question 9

What four ligaments stabilise the sternoclavicular joint?

Answer 9

• Interclavicular
• Costoclavicular
• Ant/post sternoclavicular

Question 10

What are the two subdivisions of the coracoclavicular ligament?

Answer 10

• Trapezoid
• Conoid

(Imagine a cone sitting on top of a trapezium)

Question 11

Can the glenohumeral ligament be found anteriorly or posteriorly within the joint capsule? What ligament runs between the coracoid process and the humerus?

Answer 11

• It can be found anteriorly
• Secondly, this ligament is called the coracohumeral ligament

Question 12

List four bursae of the shoulder

Answer 12

1. Subacromial
2. Subdeltoid
3. Subtendinous for subscapularis
4. Subtendinous for infraspinatus

Question 13

List the six directions of movement of the glenohumeral joint

Answer 13

• Abduction/adduction
• Internal/external rotation
• Flexion/extension

Question 14

What is the scapulohumeral rhythm? Describe it during shoulder abduction.

Answer 14

It is the relationship between the movement of the scapula and the humerus.

In arm abduction, there are 3 phases:

1. 0-30°: only humerus moves
2. 30-90°: 2 to 1 ratio, humerus moves 40°, and scapula moves 20
3. Humerus moves 60°, and scapula moves ~30°