L3 - Anatomy of the shoulder region

Question 1

What is the pectoral girdle?

Answer 1

The clavicle & scapula

Question 2

What are the skeletal components of the shoulder region?

Answer 2

Clavicle
Scapula
Humerus

Question 3

What are the two joints in the shoulder region?

Answer 3

Glenohumeral joint

Acromioclavicular joint

Question 4

What is the function of the ligaments of the shoulder

Answer 4

To stabilise/support the shoulder (they are very strong)

Question 5

What are the ligaments of the shoulder?

Answer 5

Coracoclavicular
Acromioclavicular
Coracoacromial
Glenohumeral

Question 6

How many parts to the coracoclavicular ligament?

Answer 6

Two

Sit at right angles to each other - provides added strength

Question 7

What is important about the coracoclavicular ligament?

Answer 7

It is a major stabilising ligament of the shoulder

Question 8

What is the function of the coracoacromial ligament?

Answer 8

Forms an arch
Provides support for the head of the humerus
Prevents superior dislocation of the humerus from the glenohumeral joint

Question 9

Which ligaments form a triangle?

Answer 9

Coracoclavicular and coracoacromial

Question 10

Which muscle performs abduction of the arm?

Answer 10

The deltoid (but supraspinatus initiates it)

Question 11

Describe the shape and composition of the deltoid muscle

Answer 11

Large triangular muscle

Anterior, intermediate and posterior fibres

Question 12

When the fibres all contract together what happens?

Answer 12

Abduction of the arm

Question 13

Which muscles perform adduction of the arm?

Answer 13

Latissimus dorsi

Pectoralis major

Question 14

What is the origin and insertion of latissimus dorsi?

Answer 14

Origin: Thoracolumbar fascia
Insertion: floor of the bicipital groove

Question 15

What is the origin and insertion of pec major?

Answer 15

Origin: sternum & medial clavicle
Insertion: Lateral lip of the bicipital groove

Question 16

What increases the range of movement in abduction/adduction of the arm?

Answer 16

Rotation of the scapula

Question 17

During abduction of the arm, the inferior angle of the scapula rotates in which direction?

Answer 17

Laterally

Question 18

During adduction of the arm, the inferior angle of the scapula rotates in which direction?

Answer 18

Medially

Question 19

When we raise our arms above our heads the supraglenoid fossa is brought into which position?

Answer 19

Superior orientation

Question 20

What is the composition of the trapezius?

Answer 20

Upper, middle and lower fibres

Question 21

Where do the upper fibres insert?

Answer 21

Acromion

Question 22

Which muscles contract in order to (abduct &) lift our arms up above our head?

Answer 22

Upper and lower fibres of the trapezius

Inferior digitations of serratus anterior

Question 23

Which muscles are involved in adducting the arms?

Answer 23

None - adduction of arm mostly due to gravity

Question 24

Which muscles contract in adduction of the arm against gravity (to bring arms towards horizontal from above our heads)?

Answer 24

Levator scapulae

Rhomboid

Question 25

Which muscles are involved in flexion of the arm?

Answer 25

Biceps brachii | Anterior fibres of the deltoid

Question 26

Describe the composition of the biceps brachii

Answer 26

Long head and short head

Question 27

What is the origin of the long head of the biceps brachii?

Answer 27

Supraglenoid tubercle of scapula (at the top of the glenoid fossa)

Question 28

What is the origin of the short head of the biceps brachii?

Answer 28

Apex of coracoid process

Question 29

What movement does the coracobrachialis help with?

Answer 29

Bringing the arm across the torso

Question 30

What muscle extends the arm?

Answer 30

Triceps brachii

Question 31

What is the composition of the triceps brachii?

Answer 31

Long, lateral and medial heads

Question 32

What is the origin of each head of triceps brachii?

Answer 32

Long head: infraglenoid tubercle of scapula Medial head: posterior surface of shaft of humerus Lateral head: posterior surface of shaft of humerus

Question 33

What is the insertion of all heads of the triceps brachii?

Answer 33

Olecranon

Question 34

What is the insertion of biceps brachii heads?

Answer 34

Radial tuberosity

Question 35

The lateral and medial heads of the triceps brachii have nothing to do with the shoulder, their sole purpose is to:

Answer 35

Extend the arm at the elbow

Question 36

Why is the glenohumeral joint hugely unstable?

Answer 36

Large humeral head | Shallow glenoid fossa

Question 37

Which is the mostly frequently dislocated joint?

Answer 37

Glenohumeral joint

Question 38

What dislocation of the glenohumeral joint is common?

Answer 38

Anterior dislocation - humeral head descends inferiorly and ends up anterior

Question 39

Name the soft tissue structures whose function it is to prevent dislocation of the shoulder joint?

Answer 39

1. Coracoacromial arch 2. Glenohumeral ligaments 3. Deepening of the glenoid fossa by the glenoid labrum 4. Long heads of biceps (above) and triceps (below) 5. Tendons of rotator cuff muscles

Question 40

The coracoacromial arch is formed by which ligament?

Answer 40

Coracoacromial ligament

Question 41

Why is the coracoacromial arch important?

Answer 41

It forms the void for the head of the humerus & prevents SUPERIOR DISLOCATION of glenohumeral joint

Question 42

How many glenohumeral ligaments are there and what is their function?

Answer 42

Three: superior, middle & inferior | To support the anterior of the glenohumeral joint

Question 43

Function of the glenoid labrum?

Answer 43

Deepens the glenoid fossa by increasing surface area and providing a more snug fit for the head of the humerus to reduce risk of injury

Question 44

What is the TRANSVERSE HUMERAL LIGAMENT?

Answer 44

Covers the bicipital groove Tendon of the long head of biceps brachii goes through the bicipital groove THL prevents the tendon of biceps brachii slipping out

Question 45

How many rotator cuff muscles are there?

Answer 45

``` Four: Supraspinatus Infraspinatus Subscapularis Teres minor ```

Question 46

What is the function of the rotator cuff muscles?

Answer 46

Fuse with the joint capsule | Form a cuff around the joint and stabilise it

Question 47

Where do the rotator cuff muscles insert?

Answer 47

Proximal end of the humerus close to joint

Question 48

The rotator cuff muscles surround the joint on all sides except:

Answer 48

Inferiorly - this is why anterior dislocation is most common

Question 49

Where does the tendon of the supraspinatus pass?

Answer 49

Superiorly over the joint

Question 50

Where does the tendon of the infraspinatus and teres minor pass?

Answer 50

Posteriorly to the joint

Question 51

What is the function of the bursa?

Answer 51

They protect the tendon they sit above

Question 52

The tendon of the subscapularis passes?

Answer 52

Anteriorly to the joint

Question 53

Where does the subacromial bursa sit?

Answer 53

Above the infraspinatus tendon

Question 54

Where does the axillary nerve pass through?

Answer 54

Quandrangular space, below teres minor and around the surgical head of the humerus

Question 55

What are the three facets of the greater tubercle and what inserts on these?

Answer 55

Uppermost facet: Supraspinatous inserts Middle facet: Infraspinatous inserts Lowest facet: Teres minor inserts

Question 56

What is the function of the rotator cuff muscles?

Answer 56

Together stabilise the head of the humerus on the glenoid fossa

Question 57

Tonic contraction of all the rotator cuff muscles forces...?

Answer 57

Forces the head of the humerus against the glenoid fossa

Question 58

Abduction of the arm by contraction of the deltoid occurs best when there is already a 15 degrees angle away from the body - which is achieved through contraction of which muscle?

Answer 58

Supraspinatus

Question 59

Subscapularis contraction leads to which movement?

Answer 59

Medial rotation of the scapula

Question 60

Teres major is not a true rotator cuff muscle - true or false?

Answer 60

True

Question 61

Teres major performs which action?

Answer 61

Medial rotation of the scapula

Question 62

Teres major contracts against which muscle in abduction and why?

Answer 62

Deltoid | TM stabilises humerus during abduction

Question 63

What is the blood supply to the rotator cuff muscles?

Answer 63

Provided by the scapular anastomosis

Question 64

Which arteries contribute to the scapular anastomosis?

Answer 64

Suprascapular & dorsal scapular arteries - branches of the subclavian arteries Subscapular - branch of the axillary artery

Question 65

What is the significance of the scapula anastomosis?

Answer 65

Allows continuous supply of blood to the shoulder region during movement

Question 66

What is the most common rotator cuff injury?

Answer 66

Supraspinatus impingement

Question 67

Why is supraspinatus impingement the most common RC injury?

Answer 67

Because there is limited space for the supraspinatus tendon below the coracoacromial arch

Question 68

When does impingement of the supraspinatus tendon occur?

Answer 68

Due to repetitive overhead activities & when doing the front crawl - common in athletes (throwers)

Question 69

Where does the nerve supply to the shoulder come from?

Answer 69

Brachial plexus

Question 70

Which cord is the main nerve supplying the shoulder region?

Answer 70

Posterior cord of brachial plexus

Question 71

What does the posterior cord terminate as?

Answer 71

Axillary and radial nerves

Question 72

Which muscles are supplied by the axillary nerve?

Answer 72

Deltoid | Teres minor

Question 73

Which muscles are supplied by the radial nerve?

Answer 73

Triceps brachii

Question 74

Which muscles are supplied by the upper and lower sub scapular nerves?

Answer 74

Subscapularis | Teres major

Question 75

The upper and lower sub scapular nerves come off which cord?

Answer 75

Posterior cord

Question 76

Damage to the axillary nerve results in?

Answer 76

Loss of sensation to the lateral aspect of the arm | May not be able to abduct arm because axillary nerve supplies the deltoid muscle

Question 77

The medial pectoral nerve is branch from which cord?

Answer 77

Medial cord

Question 78

The medial cutaneous nerves are branches from which cord?

Answer 78

Medial cord

Question 79

The medial cutaneous nerves supply which side of the upper limb?

Answer 79

Medial side of arm and forearm

Question 80

The lateral cord terminates as?

Answer 80

Musculocutaneous nerve | Lateral part of Median nerve

Question 81

The medial cord terminates as?

Answer 81

Medial part of Median nerve | Ulnar nerve