2 Shoulder

Question 1

How is stability of the pectoral girdle maintained?

Answer 1

By muscles attaching scapula to trunk:
Rhomboids.
Levator scapulae.
Trapezius.
Serrates anterior.

Question 2

Attachment, function and innervation of trapezius.

Answer 2

Spine to clavicle/ acromion process/ spine of scapula.
Elevate, retract and depress scapula.
Accessory nerve (CNXI).

Question 3

Attachment, function and innervation of deep dorsal muscles (lev scap, rhomboids).

Answer 3

Medial border of scapula to spinous process C1-T5.
Elevate, rotate medially.
Retract medially and superiorly.
Dorsal scapular nerve (C5).

Question 4

Attachment, function and innervation of serratus anterior.

Answer 4

Ribs to medial border scapula.
Protracts scapula and rotates laterally.
Long thoracic nerve (C5-7).

Question 5

What is winged scapula? What causes it?

Answer 5

Medial border and inferior angle of scapula pull away from posterior thoracic wall. Damage to the long thoracic nerve (superficial to serratus anterior).

Question 6

What improve the stability of the glenohumeral joint?

Answer 6

Glenoid labrum, ligaments, biceps tendon, rotator cuff muscles.

Question 7

What is the coraco-acromial arch made of and what does it do?

Answer 7

Acromion, coracoid process, coracoacromial ligament.

Prevents superior displacement of humerus.

Question 8

What is painful arc syndrome?

Answer 8

Males >50yo.
Excessive inflammation.
Pain during 50-130o. When subacromial bursa is in contact with acromion.

Question 9

What are the rotator cuff muscles?

Answer 9

Supraspinatus.
Infraspinatus.
Teres minor.
Subscapularis.

Question 10

Attachment, function and innervation of the posterior rotator cuff muscles.

Answer 10

Fossa of scapula to greater tubercle.
Spinatus’:suprascapular nerve.
Teres minor: axiallary nerve.
Abduct and laterally rotates arm.

Question 11

Attachment, function and innervation of subscapularis.

Answer 11

Subscapular fossa to lesser tubercle.
Upper+lower subscapular nerves.
Medially rotates + adducts arm.

Question 12

Attachment, function and innervation of teres major.

Answer 12

Inferior angle of scapula to inter tubercular of humerus.
Lower subscapular nerve.
Adducts and medially rotates arm.

Question 13

What is the test for supraspinatus function?

Answer 13

Abduct arm fully, then lower with control. Arm will fall suddenly at 90o.

Question 14

Which direction do most shoulder dislocations occur in?
Which nerve does this damage?
How does this present?

Answer 14

Anteroinferior.
Axillary nerve.
Flattened shoulder, deltoid atrophy + military badge anaesthesia.

Question 15

How does abduction occur at the shoulder joint?

Answer 15

Supraspinatus initiates, deltoid takes over.

Beyond 90o teres minor laterally rotates humerus; trapezius and serratus anterior laterally rotate scapula.

Question 16

What are the boundaries of the quadrangular space?

Answer 16

Surgical neck of the humerus, long head of triceps brachia, teres major, teres minor.

Question 17

What are the contents of the quadrangular space?

Answer 17

Axillary nerve.

Posterior circumflex humeral artery and vein.

Question 18

What is quadrangular space syndrome?

Who does it affect?

Answer 18

Transient nerve blockage caused by fibrotic bands.
Uncommon. Found in sports players with overhead moments during abduction, extension and external rotation.
Pain and paraesthesia down the arm.