Upper Limb - Shoulder (1.2)

Question 1

Name the four joints of the shoulder.

Answer 1

1. Glenohumeral
2. Acromioclavicular
3. Sternoclavicular
4. Scapuluthoracic

Question 2

What is the basic function of all the rotator cuff muscles?

Answer 2

On contraction, they hold the humeral head in the glenoid fossa, and they do this regardless of whether the humerus is being adducted, abducted, extended, rotated, etc.

Question 3

Name the muscles of the rotator cuff.

Answer 3

Subscapularis.
Supraspinatus.
Infraspinatus.
Teres minor.

Question 4

What is the innervation to each muscle of the rotator cuff?

Answer 4

Subscapularis: Subscapular nerve.
Supraspinatus + Infraspinatus : Suprascapular nerve (the one that goes over the top of the anterior scapula, and down the back of it.)
Teres minor: Axillary nerve.

Question 5

Name two bursae in the shoulder.

Answer 5

Subacromial bursa (important in supraspinatus impingement)
Subscapular bursa (continuous with the synovial cavity of the joint)

Question 6

What is the mnemonic SSIT? Which muscles attach to the greater tubercle, and which to the lesser tubercle?

Answer 6

This is the attachments of the muscles of the rotator cuff. Subscapularis attaches anteriorly at the lesser tubercle, whilst Supraspinatus, Infraspinatus and Teres Minor attach posteriorly at the greater tubercle of the humerus.

Question 7

What type of joint is the acromio-clavicular joint?

Answer 7

A plane type of synovial joint.

Question 8

Describe the ligaments of the acromioclavicular joint.

Answer 8

1. Coracoclavicular ligament (made up of the Conoid ligament and the Trapezoid ligament)
2. Acromioclavicular ligment
   Note that the coracoacromial ligament is said to be part of the glenohumeral joint, because it prevents superior dislocation.

Question 9

Describe the ligaments of the glenohumeral joint.

Answer 9

1. Glenohumeral ligaments anteriorly (three fibrous bands)
2. Coracohumeral ligament superiorly
3. Coracroacromial ligament (extrinsic ligament)