Articular System 2 - Shoulder Joint

Question 1

Identify the major joints of the upper limb?

Answer 1

Question 2

Define the types of major joints according to the structural and functional classification?

Sternoclavicular Joint
Acromioclavicular Joint
Shoulder Joint
Elbow Joint
Proximal Radio-Ulnar Joint
Distal Radio-Ulnar Joint

Answer 2

Sternoclavicular Joint = saddle synovial joint (acts as ball-and-socket).

Acromioclavicular Joint = plane synovial joint.

Shoulder Joint = ball-and-socket synovial joint.

Elbow Joint = hinge synovial joint.

Proximal Radio-Ulnar Joint = pivot synovial joint.

Distal Radio-Ulnar Joint = pivot synovial joint.

Question 3

Define the types of major joints according to the structural and functional classification?

Middle Radio-Ulnar Joint
Radiocarpal (wrist) Joint
Carpometacarpal Joint of Thumb
2nd to 5th Carpometacarpal Joints
Metacarpophalangeal Joints
Interphalangeal Joints

Answer 3

Middle Radio-Ulnar Joint = fibrous syndesmosis joint.

Radiocarpal (wrist) Joint = condyloid synovial joint

Carpometacarpal Joint of Thumb = saddle synovial joint

2nd to 5th Carpometacarpal Joints = plane synovial joints.

Metacarpophalangeal Joints = condyloid synovial joints.

Interphalangeal Joints = hinge synovial joints.

Question 4

Describe the function/movement of the shoulder joint?

Answer 4

1. Flexion/extension
2. Abduction/adduction
3. Medial/lateral rotation
4. Circumduction

Question 5

Label the parts of the shoulder joint?

Answer 5

Question 6

Label the parts of the shoulder joint?

Answer 6

Question 7

Describe the structure of the shoulder joint?

(Static stabilisers: ligaments)

Answer 7

Question 8

Where do the muscles of the scapula originate from and where do they insert?

Answer 8

Originates at the posterior aspect of the scapula:
1. Supraspinatus
2. Infraspinatus
3. Teres minor

Originates at the anterior aspect of the scapula:
1. Subscapularis

Insertion:
* All 4 muscles insert at the proximal humerus.

Question 9

What is the function of the subacromial (subdeltoid) bursa?

Answer 9

Provides cushioning

Question 10

Why does the shoulder joint dislocate easily?

Answer 10

Highly mobile = very unstable (inverse relationship).

Question 11

How do the rotator cuff muscles support the shoulder joint?

Answer 11

They keep the humeral head in the joint capsule and rotate it at the shoulder joint.

Question 12

What is the scapulothoracic joint?

Answer 12

• It is not a true joint.
• Instead, it is a functional articulation between the scapula and the thoracic cage (rib cage) at the back of the body.