Joint structures and classification of the upper limb

Question 1

Joints of shoulder girdle

Answer 1

• Sternoclavicular joint (SC joint)
• Acromioclavicular joint (AC joint)
• Glenohumeral joint (GH joint)
• Scapulothoracic ‘joint’ (not a real joint)

Question 1

Sternoclavicular (SC) joint

Answer 1

• Articulation between the clavicle and sternum
• Saddle synovial joint - however it functions like a ball & socket joint
• Articular disc – fibrocartilage, shock absorber

Question 2

Ligaments of the sternoclavicular joint

Answer 2

• Anterior and posterior sternoclavicular ligaments
• Interclavicular ligament
• Costoclavicular ligament

Question 3

Movements and nerve supply of the sternoclavicular joint

Answer 3

Movements
- Protraction & retraction of the clavicle
- Elevation & depression of clavicle
- Rotation about the longitudinal axis – assists the above movements
- Circumduction (a combination of the above movements)
Nerve supply
* Medial supraclavicular nerve
* Nerve to subclavius

Question 4

Acromioclavicular Joint (AC)

Answer 4

• Articulation between clavicle and acromion of the scapula
• Plane type of synovial joint
• Articular disc - fibrocartilage

Question 5

Ligaments of the acromioclavicular joint

Answer 5

• Acromioclavicular ligament
• Coracoclavicular ligament
• Coracoacromial ligament

Question 6

Movements and nerve supply of the acromioclavicular joint

Answer 6

Movements
- Acromion of the scapula glides on the acromial end of the clavicle as the scapula moves on the thoracic cage
- Axioappendicular muscles move the scapula which in turn moves the acromion on the clavicle
Nerve supply
- lateral supraclavicular nerve
- lateral pectoral nerve
- axillary nerve

Question 7

Glenohumeral joint

Answer 7

• Articulation of the humoral head and the glenoid fossa of the scapula
• Ball and socket so its multiaxial

Question 8

Ligaments of the glenohumeral joint

Answer 8

• Glenohumeral ligaments
• Transverse humeral ligament
• Coracohumeral ligament
• Coracoacromial ligament

Question 9

Movements and nerve supply of the glenohumeral joint

Answer 9

Movements
- Flexion/extension
- Abduction/adduction
- Internal (medial) and external (lateral) rotation
- Circumduction
Bursa
- Subacromial bursa
- Subscapular bursa
Nerve supply
- Axillary nerve
- Suprascapular nerve
- Lateral pectoral nerve

Question 10

Glenoid labrum

Answer 10

• A fibrocartilaginous ring-like structure that lines the outer rim of the glenoid fossa
  Function:
  increases stability of the joint.
  Increases depth of fossa

Question 11

Coracoacromial arch

Answer 11

Formed by
- Coracoid process
- Acromial process (acromion)
- Coracoacromial ligament
Function
- Supraspinatus muscle/tendon and tendon of long head of biceps brachii pass beneath the arch in the ‘subacromial space’

Question 12

Hiltons law

Answer 12

The nerve/s which innervate a joint also innervate the muscles which move that joint

Question 13

Proximal Radioulnar Joint

Answer 13

Type: Pivot-type synovial

Articulation: Head of radius ↔ Radial notch of ulna

Function: Allows pronation and supination.

Question 14

Distal Radioulnar Joint

Answer 14

Type: Pivot-type synovial

Articulation: Head of ulna ↔ Ulnar notch of radius

Function: Rotation of the radius around the ulna during pronation/supination.

Question 15

Radiocarpal Joint (Wrist Joint)

Answer 15

Type: Condyloid (ellipsoid) synovial