Shoulder anatomy and conditions

Question 1

What is the function of the glenoid labrum?

Answer 1

Increases capture of the humeral head

Question 2

What does the trapezius muscle do? What are it’s origins and insertions?

Answer 2

Elevates/depresses the scapula. Origins on thoracic vertebrae/occipital bone, inserts onto spine of scapula

Question 3

What are the rotator cuff muscles and their function?

Answer 3

Supraspinatus- abduction Infraspinatus- external rotation Teres minor- external rotation Subscapularis- internal rotation Overall- stabilise the shoulder girdle

Question 4

Three of the rotator cuff muscles share an insertion. What is this, and which muscle is the exception to this?

Answer 4

Greater tubercle of humerus Subscapularis inserts onto lesser tubercle of humerus

Question 5

Where does the deltoid muscle attach and what is its function?

Answer 5

Attaches to the deltoid tuberosity on the lateral aspect of the humerus

Question 6

What are the origins of the long arm and short arm of biceps brachii, and what is their common insertion?

Answer 6

Short- coracoid process Long- labrum/glenoid

Question 7

What is impingement?

Answer 7

Compression of the rotator cuff tendons within the tight subacromial space. Possible causes: inferior acromial osteophyte, bursitis, hooked acromion, rotator cuff tear, tendonitis

Question 8

What signs are seen upon clinical examination in impingement?

Answer 8

Painful arc Pain on Hawkins-Kennedy test

Question 9

How is impingement managed?

Answer 9

Initially- most settle with NSAIDs, physio, steroid injections Refractory- may require subacromial decompression surgery

Question 10

How do rotator cuff tears typically happen in a) younger people b) older people

Answer 10

a) traumatic- e.g. shoulder disclocation b) minimal trauma- usually due to underlying degenerate changes in tendon. Typical history is of a sudden jerk followed by shoulder pain and weakness

Question 11

How can rotator cuff tears be managed?

Answer 11

Controversial: - physio can help strengthen other muscles to compensate - surgicalrepair of the muscle may fail due to underlying tendon disease

Question 12

What may be the result of chronic rotator cuff insufficiency?

Answer 12

Osteoarthritis of the glenohumeral joint

Question 13

Describe the typically history of adhesive capsulitis.

Answer 13

Takes place over about 18-24 months- pain followed by stiffness, followed by gradual “thawing” of the stiffness

Question 14

What is the principal clinical sign in adhesive capsulitis?

Answer 14

Loss of external rotation

Question 15

What other diseases are associated with adhesive capsulitis?

Answer 15

Diabetes Hypercholesterolaemia Dupuytren’s disease

Question 16

How is adhesive capsulitis managed?

Answer 16

Conservative- analgesics and physio Once pain has settled- can relieve stiffness by manipulation under anaesthetic (MUA) or capsular release (tears the capsule)

Question 17

What are the two main patterns of shoulder instability?

Answer 17

Traumatic (e.g. past dislocation which doesn’t stabilize, predisposing to subluxation/dislocation with minimal force) Atraumatic- people with generalised ligamentous laxity (Ehler’s-Danlos, Marfan’s)

Question 18

How does a dislocated shoulder appear?

Answer 18

Loss of roundness of the shoulder and loss of symmetry

Question 19

How is shoulder dislocation managed?

Answer 19

Closed reduction under sedation/anaesthesia, followed by imaging to confirm the reduction. Patient is placed in a sling for two weeks, followed by physiotherapy. Delayed presentation may require open reduction with internal fixation

Question 20

Approximately what percentage of patients suffering a shoulder dislocation under the age of 20 will present with a further dislocation at some point?

Answer 20

Around 80%

Question 21

How does damage to the axillary nerve in shoulder dislocation often present?

Answer 21

Loss of sensation in the “regimental badge” area

Question 22

What is the typical mechanism of injury in a proximal humeral fracture?

Answer 22

Fall onto outstretched hand in osteoporotic patient

Question 23

What is the typical fracture appearance in a proximal humeral fracture?

Answer 23

Fracture of surgical neck of femur, with medial displacement of the shaft due to pull of pectoralis muscles

Question 24

How are a) marginally displaced and b) displaced proximal humeral fractures treated?

Answer 24

a) conservatively with a sling, anelgesia b) ORIF

Question 25

How do most humeral shaft fractures happen?

Answer 25

Direct or indirect trauma

Question 26

What is the most common complication of humeral shaft fracture?

Answer 26

Damage to the radial nerve- manifest by wrist drop and lost of sensation in the first dorsal web space

Question 27

Answer 27

From top right: clavicle, coracoclavicular ligaments, scapula, biceps, humerus, coracoacromial ligament, acromion, acromioclavicular joint

Question 28

Answer 28

Left image from top left: clavicle, coracoclavicular ligament, acromioclavicular joint, aromion, coracoacriomal ligament, coracoid process, humerus, subscapularis, scapula

Right image from top right: supraspinatus, infraspinatus, scapula, teres minor, humerus, acromion, clavicle