T2 L3 Anatomy of the shoulder region

Question 1

What are the skeletal components of the shoulder?

Answer 1

Pectoral girdle - clavicle and scapula

Humerus

Question 2

What are the 2 joints in the shoulder?

Answer 2

Glenohumeral joint

Acromioclavicular joint

Question 3

What are the 4 ligaments of the shoulder region?

Answer 3

Coracoclavicular
Acromoclavicular
Coracoacromial
Glenohumeral

Question 4

What is the coracoclavicular ligament between?

Answer 4

Clavicle and coracoid process of scapula

Question 5

What is the function of the acromoclavicular ligament?

Answer 5

Forms a capsule around the acromoclavicular joint to strength and stabilise the joint

Question 6

What is the coracoacromial ligament between?

Answer 6

Between coracoid process and acromion

Question 7

What is the function of the coracoacromial ligament?

Answer 7

Forms coraco-acromial arch over top of glenohumeral joint

Provides support for head of humerus to prevent superior dislocation

Question 8

What are the movements of the glenohumeral joint?

Answer 8

Abduction / adduction
Flexion / extension
Lateral / medial rotation
Circumduction

Question 9

What parts is the glenohumeral joint split into?

Answer 9

Superior
Middle
Inferior

Question 10

What is abduction mainly performed by?

Answer 10

Deltoid

Question 11

What is the origin, insertion, function and innervation of the deltoid muscle?

Answer 11

Origin: spine of scapula, acromion, clavicle
Insertion: deltoid tuberosity
Innervation: axillary nerve
Function: abduction
- anterior fibres: flexion and medial rotation
- posterior fibres: extension and lateral rotation

Question 12

What is adduction performed by?

Answer 12

Latissimus dorsi

Pectoralis major

Question 13

What is the origin, insertion, function and innervation of latissimus dorsi?

Answer 13

Origin: thoracolumbar fascia, spinous process T6-T12, iliac crest, inferior 3 ribs
Insertion: bicipital groove of humerus
Function: adduction and medial rotation
Innervation: dorsal scapular nerve

Question 14

What is the origin, insertion, function and innervation of pectoralis major?

Answer 14

Origin: sternum, medial part clavicle, costal cartilage
Insertion: lateral lip bicipital groove
Function: adduction, flexion, medial rotation
Innervation: pectoral nerves

Question 15

What helps abduction above 90 degrees?

Answer 15

Upper fibres trapezius
Lower fibres trapezius
Serratus anterior

Question 16

What helps adduction above 90 degrees?

Answer 16

Most of it is gravity
Levator scapulae
Rhomboids

Question 17

What muscles are involved in flexion of the arm?

Answer 17

Short head of biceps
Long head of biceps
Coracobrachialis
Anterior fibres deltoid

Question 18

What muscles are involved in extension of the arm?

Answer 18

Long head of triceps
Lateral and medial heads of triceps
Posterior fibres of deltoid
Latissimus dorsi

Question 19

Why is the glenohumeral joint unstable?

Answer 19

Large humeral head

Shallow glenoid fossa

Question 20

What is the most frequently dislocated joint?

Answer 20

Glenohumeral joint

Anterior dislocation where humeral head descends inferior to end up anterior

Question 21

What 5 factors increase the stability of the glenohumeral joint to prevent dislocation?

Answer 21

Coracoacromial arch
Glenohumeral ligaments
Deepening of glenoid fossa by glenoid labrum
Long heads of biceps and triceps
Tendons of rotator cuff muscles

Question 22

Why does the coracoacromial arch prevent glenohumeral dislocation?

Answer 22

Prevents superior displacement of humeral head to prevent superior dislocation

Question 23

How do the glenohumeral ligaments prevent dislocation?

Answer 23

Supports the joint anteriorly

Between rim of glenoid fossa and anatomical neck of humerus

Question 24

What is the glenoid labrum?

Answer 24

Fibrocartilaginous ridge surrounding glenoid cavity

Creates a seal with the head of the humerus to reduce the risk of dislocation

Question 25

What are the 4 rotator cuff muscles?

Answer 25

Supraspinatus Infraspinatus Teres minor Subscapularis

Question 26

What is the origin, insertion and function of supraspinatus

Answer 26

Sits superior over joint Origin: supraspinous fossa Insertion: greater tubercle Function: initiate abduction

Question 27

What is the origin, insertion and function of infraspinatus?

Answer 27

Sits posterior over joint Origin: infraspinous fossa Insertion: greater tubercle Function: lateral rotation

Question 28

What is the origin, insertion and function of teres minor?

Answer 28

Sits posterior over joint Origin: infraspinous fossa Insertion: greater tubercle Function: lateral rotation

Question 29

What is the origin, insertion and function of subscapularis?

Answer 29

Sits anterior over joint Origin: subscapular fossa of scapula Insertion: lesser tubercle of humerus Function: medial rotation

Question 30

Why is the most common route for dislocation inferiorly?

Answer 30

There is no inferior rotator cuff muscle

Question 31

What is the function of the subacromial bursa?

Answer 31

Reduces friction beneath deltoid to promote free motion of rotator cuff tendons

Question 32

Where does teres major sit?

Answer 32

Inferior to teres minor

Question 33

Why is teres major not a true rotator cuff muscle?

Answer 33

It doesn't cuff the joint

Question 34

What is the origin, insertion and function of teres major?

Answer 34

Origin: inferior angle of scapula Insertion: medial lip bicipital groove Function: medial rotation, stabilises humerus during abduction - eccentric contraction

Question 35

Why is the supraspinatus commonly injured?

Answer 35

Limited space for tendon under coracoacromial arch | Impingement due to repetitive overhead activities

Question 36

Describe the scapula anastomosis

Answer 36

Couple of branches from subclavian and one from axillary Subscapular artery comes from 3rd part axillary Suprascapular artery comes from thyrocervical trunk which comes from subclavian artery Dorsal scapular artery comes from subclavian and runs along medial edge of scapula

Question 37

Where is the nerve supply to the shoulder from?

Answer 37

Brachial plexus

Question 38

What does the suprascapular nerve supply?

Answer 38

Supraspinatus and infraspinatus

Question 39

What are the terminal branches of the posterior division?

Answer 39

Axillary | Radial

Question 40

What does the axillary nerve supply?

Answer 40

Deltoid Teres major Badge area of skin

Question 41

What does the radial nerve supply?

Answer 41

Extensors such as triceps brachii

Question 42

What other branches come from the posterior cord?

Answer 42

Upper / lower subscapular nerves | Thoracodorsal nerves

Question 43

What do the subscapular nerves supply?

Answer 43

Subscapularis | Teres major

Question 44

What does the thoracodorsal nerve supply?

Answer 44

Latissimus dorsi

Question 45

What are the borders of the quadrangular space?

Answer 45

Teres minor Teres major Long head of triceps Humerus

Question 46

What is the consequence of a fracture to the cervical neck?

Answer 46

Can damage axillary artery so deltoid can't work so can't abduct arm

Question 47

What are the terminal branches of the lateral cord?

Answer 47

Musculocutaneous | Median

Question 48

What does the musculocutaneous nerve supply?

Answer 48

Arm flexors

Question 49

What is another branch of the lateral cord?

Answer 49

Lateral pectoral nerve which supplies pectoralis major

Question 50

What are the terminal branches of the medial cord?

Answer 50

Median | Ulnar

Question 51

What are some other branches of the medial cord?

Answer 51

Medial pectoral nerve | Medial cutaneous nerves

Question 52

What does the medial pectoral nerve supply?

Answer 52

Pectoralis major / minor