Shoulder Region

Question 1

Scapulothoracic joint is considered a ___ joint because?

Answer 1

False because there is no direct bone to bone articulation (it floats)

Question 2

1. Where on the humerus does the axillary nerve form anastomoses?
2. Why is this anastomoses formed?

Answer 2

1. The surgical neck of the humerus

2. It’s formed so if there is injury, regions are still able to get blood supply to help prevent necrosis

Question 3

Deltoid

Origin
Insertion
Innervation
Action

Answer 3

Origin: lateral 1/3 of clavicle, acromion and spine of scapula

Insertion: deltoid tuberosity

Innervation: axillary nerve

Action: anterior = flexion and medial rotation of the humerus; middle = abduction of humerus 15-90 degrees; posterior= extension and lateral rotation

Question 4

Supraspinatus and infraspinatus

Origin
Insertion
Innervation
Action

Answer 4

Origin: S= supraspinous fossa
I= infraspinous fossa

Insertion: greater tuberosity of humerus

Innervation: suprascapular nerve

Action: S= abduction from 0-15 degrees
I= lateral rotation of the humerus

Question 5

Teres minor

Origin
Insertion
Innervation
Action

Answer 5

Origin: lateral border of scapula

Insertion: greater tuberosity of humerus

Innervation: axillary nerve

Action: lateral rotation of humerus

Question 6

Teres major

Origin
Insertion
Innervation
Action

Answer 6

Origin: lateral border of scapula

Insertion: bicipital groove of humerus

Innervation: lower subscapular nerve

Action: extension, adduction, and medial rotation

Question 7

Subscapularis

Origin
Insertion
Innervation
Action

Answer 7

Origin: subscapular fossa

Insertion: lesser tuberosity of humerus

Innervation: upper and lower subscapular nerves

Action: medial rotation of the humerus

Question 8

1. Where is the site of potential weakness in the rotator cuff? Why?
2. Where is the most common sister of rotator cuff injury?

Answer 8

1. Deficient inferiorly because the rotator cuff muscles form a tendinous cuff around the shoulder and only cover the anterior, posterior and superior aspects
2. Supraspinatus tendon

Question 9

Patients with rotator cuff injury will present with what 3 things?

Answer 9

Pain, shoulder instability, and limited ROM

Question 10

1. What are the 5 nerves of the brachial plexus?

2. Which is the main one of the shoulder region?

Answer 10

1. Axillary, radial, ulna, median and musculocutaneous

2. Main is axillary

Question 11

1. Where does the axillary nerve pass through that makes it vulnerable to damage during shoulder dislocations?
2. Muscular branches of axillary nerve go to what 2 muscles?
3. Upper lateral cutaneous nerve is branch of axillary that supplies the skin of what region?

Answer 11

1. Inferior to shoulder joint
2. Deltoid and teres minor
3. Superior part of lateral aspect of the arm

Question 12

The main artery of the brachial plexus goes through two name changes as it moves down the arm. What are the 3 names (from proximal to distal)

Answer 12

Subclavian artery, axillary artery, and brachial artery

Question 13

1. Axillary artery has 3 branches; what arteries are in each branch?
2. One of the arteries of the second part has 4 terminal branches; which artery and what are they?

Answer 13

1. 1st part: superior thoracic artery

2nd part: thoracoacromial artery and lateral thoracic artery

3rd part: subscapular artery, anterior circumflex artery, and posterior circumflex artery

2. Thoracoacromial artery immediately divides into clavicular, acromial, deltoid, and pectoral branches

Question 14

There are two branches of the subclavian artery involved in anastomosis around shoulder region; what are they?

Which part of the axillary artery branches is involved in anastomosis around shoulder?

Answer 14

Suprascapular artery and superficial cervical artery

All 3 branches of the 3rd part of the axillary artery

Question 15

5 bursae of the shoulder joint

Answer 15

Subscapularis bursa, infraspinatus bursa, subacromial bursa, subdeltoid bursa, and subcutaneous acromial bursa

Question 16

Quadrangular space

1. Borders?
2. Contents?

Answer 16

1. Medial: long head of triceps
   Lateral: humeral shaft
   Superior: teres minor
   Inferior: teres major
2. Axillary nerve and posterior humeral circumflex artery

Question 17

Triangular space

1. Borders
2. Contents

Answer 17

1. Inferior: teres major
   Lateral: long head of triceps
   Superior: lower border of teres minor
2. Scapular circumflex artery

Question 18

Triangular interval

1. Borders
2. Contents

Answer 18

1. Superior: teres major
   Lateral: lateral head of triceps or the humerus
   Medial: long head of the triceps
2. Contents: profunda brachii artery and radial nerve

Question 19

Articular surfaces of the glenohumeral joint?

Main support of this joint?

Answer 19

Head of the humerus and glenoid cavity of scapula

The RTC muscles (few ligamentous support; glenoid labrum and coracohumeral)

Question 20

Shoulder joint:

1. Nerve supply (2)
2. Arterial (2) (one has two branches)

Answer 20

1. Axillary nerve and suprascapular nerve

2. Axillary artery (ant and post circumflex humeral artery) and suprascapular artery

Question 21

Clinical:

1. What causes frozen shoulder?
2. What happens in rheumatoid arthritis?
3. What happens in gout?

Answer 21

1. Inflammation
2. Immune system attacks the joints
3. Form of arthritis where crystals form in joints (uncommon in shoulder)

Question 22

Clinical:

1. Shoulder impingement?
2. Shoulder tendinitis?
3. Common location for clavicle fracture?
4. What happens in compartment syndrome?

Answer 22

1. Acromion presses on RTC as the arm is lifted (causes inflammation of injury in RTC)
2. Inflammation in one of the tendons of the RTC
3. Middle 3rd
4. Blood vessels are compacted, and nerves and muscles cannot get the nutrients they need