MSK - Shoulder And Back

Question 1

What lines the articulating surface of the shoulder joint?

How is the glenoid cavity deepened?

Answer 1

Hyaline cartilage

Glenoid labrum

Question 2

What makes the shoulder joint relatively unstable?

How is stability achieved? (4)

Answer 2

Shallow glenoid cavity
Disproportion of articular surfaces
Multiplanar movements
Lax capsule

Rotator cuff muscles
Other muscles
Ligaments
Capsule

Question 3

What is the capsule of the shoulder attached to?

What feature allows movement?

What allows full abduction?

Answer 3

Glenoid labrum and margins of glenoid cavity
Anatomical neck of humerus

Tough but lax

Bridges intertubular groove and dips down medially to surgical neck

Question 4

What is the purpose of the synovial membrane?

The tendon of what muscle lies within the joint cavity?

What does the tendon acquire as it enters the joint?

What does the gap in the capsule allow?

Answer 4

Line capsule and lines bone within capsule up to edge of articulating surfaces

Long head of biceps
Acquires a tubular sleeve of synovium which surrounds tendon up to its insertion

Synovium and joint cavity to be continuous with subscapular bursa

Question 5

What are the three extracapsular ligaments?

And what are their locations?

Answer 5

Coracoacrmoial ligament - between acromion and Coracoid process

Coracohumeral ligament - base of Coracoid process to anterior part of greater tubercle

Transverse humeral ligament - holds tendon of long head of biceps in place during shoulder movement

Question 6

What are the intracapsular ligaments?

Where do they extend between?

What reinforces the capsule anteriorly?

Answer 6

Three gleno-humeral ligament - Superior, middle, inferior

Glenoid labrum and humerus

Part of fibrous capsule - can only be seen from inside the capsule

Question 7

What forms the coraco acromial arch?

Answer 7

Coracoacromial ligament, acromion and coracoid process

Question 8

What type of joint is the shoulder joint?

What is another name of the shoulder joint?

What does this type of joint allow?

What commonly occurs at this joint?

Answer 8

Ball and socket type - Synovial joint

Gleno humeral joint

Wide range of movements in multiple planes

Most mobile, least stable.

Dislocations

Question 9

What are the four rotator cuff muscles?

What is the most important factor giving stability to the joint?

Answer 9

Supraspinatus
Infaspinatus
Teres minor
Subscapularis

SITS

Rotator cuff muscles

Question 10

What arch does the supraspinatus tendon pass under?

Where is the subscapularis inserted into?

Answer 10

Coraco-acromial arch

Less tubercle

Question 11

What strengthens the rotator cuff?

Answer 11

The tendons blend to form a cuff which fuses with the capsule and strengthens it

Question 12

What characteristic of the muscles holds the head a close to the glenoid capsule?

Answer 12

Tone in the muscles

Question 13

What separates the supraspinatus tendon from the Coracoacromial arch?

Answer 13

Subacromial bursa

Question 14

What are the actions of the rotator cuff muscles?

Answer 14

Stabilise the shoulder joint, holding the head of the humerus in the glenoid cavity

Supraspinatus - initiation and first 15 degree of abduction
Infraspinatus - lateral rotation of the arm
Teres minor - lateral rotation of the arm and weak adductor
Subscapularis - medial rotation of the arm

Question 15

What other muscles stabilise the shoulder joint?

Answer 15

Deltoid
Long head of biceps
Long head of triceps

Question 16

What are the two types of bursae?

Answer 16

Subacromial bursa - facilitates movement of supraspinatus tendon under the Coracoacromial arch and deltoid muscle over the shoulder joint capsule and greater tubercle of humerus

Subscapular bursa - facilitates movement of subscapularis tendon over scapula

Question 17

What is painful arc syndrome?

Answer 17

Inflammation of the subacromial bursitis - causes pain on abduction of the arm between 50 and 130 degrees

Question 18

What are the movements of the glenohumeral joint?

Answer 18

Flexion 
Extension 
Abduction
Adduction 
Medial rotation
Lateral rotation

Question 19

What muscles cause medial and lateral rotation

Answer 19

Medial - subscapularis, teres major, pec major and lat dorsal

Lateral - infraspinatus and teres minor

Question 20

What muscles cause flexion, extension, abduction and adduction of the shoulder joint?

Answer 20

Flexion - pec major, anterior fibres of deltoid, coracobrachilais and biceps brachii

Extension - posterior fibres of deltoid, lattisimus dorsi and teres major

Abduction - 0-15 = supraspinatus, 15-90 = deltoid, above 90 = rotation of scapular - trapezius, serratus anterior

Adduction - pec major, lattisimus dorsi, teres major

Question 21

What is the blood and nerve supply to the shoulder joint?

Answer 21

Blood supply = anterior and posterior circumflex humeral arteries and suprascapular artery

Nerve supply = suprascapular, Axillary nerve, lateral pectoral nerves from the brachial plexus (C5 and C6)

Question 22

What is stability of the shoulder joint provided by?

Answer 22

Tendons of the rotator cuff
Coraco acromial arch 
Glenohumeral ligaments 
Coracohumeral ligament 
Seeping glenoid cavity by labrum 
Splinting effect of the long head of biceps and long head of triceps

Question 23

In what direction is the dislocation likely to be if it is caused by a trauma on a fully abducted arm?

What is it clinically defined as and why?

Answer 23

Inferior direction

Anterior dislocation - because the humeral head locates anteriorly due to a lull of powerful adductors

Question 24

What is likely to cause recurrent dislocation?

Answer 24

Capsule and rotator cuff tear and poor healing

Question 25

How does an anterior dislocation of the shoulder appear?

Answer 25

Loss of round contour of right shoulder
It appears square
Arm supported by other hand (very painful)

Head of humerus lies anteriorly, below Coracoid process

Question 26

What nerve injury may result from a dislocation?

What else may cause the nerve injury?

What should you not test?

Answer 26

Axillary nerve injury - loss of sensation in a small area of the skin over central part of the deltoid

Fracture of surgical neck of humerus

Motor function - could cause more soft tissue damage and injury

Question 27

What is painful arc syndrome?

What does it cause?

What does it lead to?

Answer 27

Supraspinatus tendon rubbing under the Coracoacromial arch

Causes irritation and inflammation of the supraspinatus tendon/subacromial bursa

Subacromial bursitis
Supraspinatus tendionitis
Degeneration and rupture of tendons

Question 28

What are the predisposing factors to painful arc syndrome?

Answer 28

Repetitive overuse - sporting activities, work involving overhead use of arms

Older people - degenerate changes in tendons

Avascularity of supraspinatus tendon

Slight differences in anatomy may make impingement more likely

Question 29

During what degree of abduction is pain experienced

Answer 29

50-130 degrees of abduction

Question 30

What are the three groups of muscles of the back?

What muscles are in each group?

Answer 30

Superficial group - trapezius and latissimus dorsi

Deep muscles - levator scapulae and rhomboids

Scapula-humeral - deltoid, teres major and 4 rotator cuff muscles

Question 31

What nerve innervates the trapezius?

What are the three parts of the trapezius? And what are their functions?

Answer 31

Accessory nerve

Superior part - elevates scapula
Middle part - retracts scapula
Inferior part - depresses scapula

It is a SUPERFICIAL muscle of the back

Question 32

How does the scapula rotate?

What is scapula rotation responsible for?

Answer 32

Superior and inferior parts of trapezius act together - to rotate scapula on chest wall

Serratus anterior muscle aids upward rotation of the scapula

Abduction of the arm above horizontal (90 degrees)

Question 33

Describe the latissimus dorsi.

What nerve innervates it?

Where does it extend from?

What are its functions?

Answer 33

Large, fan shaped muscle

Thoraco-dorsal nerve

Extends from; lower thoracic vertebrae, thoracolumbar fascia and iliac crest to flow of intertubercular groove

Power adductor of arm
Extends arm at shoulder
Medial rotator

It is a SUPERFICIAL muscle of the back

Question 34

What are the two deep muscles of the back?

What is their function?

What nerve innervates them?

Answer 34

Levator scapulae - elevates scapula, rotates scapula depressing glenoid cavity

Rhomboids major and minor - retract scapula, rotate scapula depressing glenoid cavity

Dorsal scapula nerve

Question 35

Name the three scapula humeral muscles of the back.

What is their function?

What nerve innervates each?

Answer 35

Deltoid muscle - important abductor of arm at shoulder joint. Powerful muscle, forms rounded part of shoulder.
Anterior fibres - flexion of arm
Middle fibres - abduct arm from 15-90 (first 15 degrees by supraspinatus muscle)
Posterior fibres - extend arm (along with Lat.dorsi)
Nerve supply = Axillary nerve

Teres major - abduct arm and medial rotator. From inferior angle or scapular to upper humerus.
Nerve - lower subscapular nerve

Rotator cuff muscles