Trauma and orthopaedics (4): The shoulder

Question 1

the scapula

Answer 1

Also known as the shoulder blades. It articulates with the humerus at the glenohumeral joint, and with the clavical at the acromioclavicular joint.

• Connects the upper limb to the trunk
• Triangular, flat bone

Question 2

the clavicle

Answer 2

The collarbone extends between the manubrium of the sternum and the acromion of the scapula.

• Long bone
• Can be palpated along its length
• In thin individuals it is visible under the skin.
• Main functions
  
  • Attaches the upper limb to the trunk as part of the shoulder girls
  • Protects the underlying neurovascular structures supplying the upper limb
  • Transmits force from the upper limb to the axial skeleton

Question 3

joints between the clavicle and scapula

Answer 3

Acromioclavicular

• Plane type synovial joint
• Located at the lateral end of the clavicle

Sternoclavicular joint

• Synovial joint between the clavicle and the manubrium of the sternum
• Only attachment of the upper limb to the axial skeleton
• Very mobile joint
• Can function more like a ball-and-socket type joint

Question 4

the shoulder joint

Answer 4

Glenohumeral joint

• ball and socket joint between the scapula and the humerus.
• synovial
• major joint connecting upper limb to trunj
• one fot he most mobile joints (at cost of joint stability)

Question 5

articulating surfaces of the glenohumeral joint

Answer 5

• Head of the humerus with the glenoid cavity of the scapula
  
  • Head of humerus= much larger than the glenoid fossa
    
    • Gives wide range of movement at the cost of inherent instability
  • To reduce disproportion in surfaces, the glenoid fossa is deepened by the glenoid labrum
    
    • Fibrocartilage rim
• Synovial joint
  
  • Articulating surfaces covered with hyaline cartilage

Question 6

stability of the glenohumeral joint

Answer 6

Rotator cuff muscles – surround the shoulder joint, attaching to the tuberosities of the humerus, whilst also fusing with the joint capsule. The resting tone of these muscles act to compress the humeral head into the glenoid cavity.

Glenoid labrum – a fibrocartilaginous ridge surrounding the glenoid cavity. It deepens the cavity and creates a seal with the head of humerus, reducing the risk of dislocation.

Ligaments – act to reinforce the joint capsule, and form the coraco-acromial arch.

Biceps tendon – it acts as a minor humeral head depressor, thereby contributing to stability.

Question 7

synovial membrane of the shoulder joint

Answer 7

• Lines the inner surface of the joint capsule and produces synovial fluid to reduce friction between the articular surfaces

Question 8

synovial bursa of the shoulder

Answer 8

Bursa

To reduce friction several synovial bursae are present- cushion between tendons and other joint structures

Subacromial -located deep to the deltoid and acromion, and superficial to the supraspinatus tendon and joint capsule. Reduces friction beneath the deltoid, promoting free motion of the rotator cuff tendons

Subscapular – located between the subscapularis tendon and the scapula. It reduces wear and tear on the tendon during movement at the shoulder joint.

Question 9

Factors that contribute towards mobility of glenohumeral joint

Answer 9

• Type of joint- ball and socket
• Bony surfaces- shallow glenoid cavity and large humeral head
  
  • 1:4 disproportion in surfaces
  • Commonly used analogy is gold ball and tee
• Inherent laxity of joint capsule

Question 10

Factors that contribute towards stability

Answer 10

• Rotator cuff muscles
• Glenoid labrum- fibrocartilaginous ridge surrounding the glenoid cavity
  
  • Deepens the cavity and creates a seal with the head of the humerus-n reducing risk of dislocation
• Ligaments- act to reinforce the joint capsule- forms the coracoacromial arch
• Biceps tendon- acts as a minor humeral head depression

Question 11

rotator cuff muscles

Answer 11

subscapularis

supraspinatus

infraspinatus

teres minor

Question 12

arterial supply of the glenohumeral joint

Answer 12

anterior and posterior circumflex humeral arteries (branches of the axillary artery (branches of the suprascapular artery also contribute)

Question 13

nervous supply of the glenohumeral joint

Answer 13

axillary, suprascapular and lateral pectoral nerve

Question 14

muscle compartments of the upper limb can be divided into

Answer 14

intirnsic and extrinsic muscles

Question 15

extrinsic muscle

Answer 15

Originates from the torso (trunk) and attach to the bones of the shoulder (clavicle, scapula and humerus). Located in the back- also known as the superficial back muscles.

Muscles are organised into two layers: Superficial layer and a deep layer

Question 16

superficial extrinsic muscles

Answer 16

trapezius

latissimus dorsi

Question 17

deep extrinsic muscles

Answer 17

levator scapulae

rhomboids

• minor
• major

Question 18

intrinsic muscles

Answer 18

Originate from the scapula and/or clavicle and attach to the humerus. Six muscles- the deltoid, teres major, and 4 rotator cuff muscles (supraspinatus, infraspinatus, subscapularis and teres minor)

Question 19

important areas found within the shoulder region

Answer 19

brachial plexus

axilla region

Question 20

brachial plexus

Answer 20

The brachial plexus is a network of nerve fibres that supplies the skin and musculature of the upper limb. It begins in the root of the neck, passes through the axilla, and runs through the entire upper extremity.

The plexus is formed by the anterior rami (divisions) of cervical spinal nerves C5, C6, C7 and C8, and the first thoracic spinal nerve, T1.

Acronyms

Real Teenagers Drink Cold Beer- roots, trunks, divisions, cords, branches

Men Are Mean Really Usually- musculocutaneous, axially, median, radial, ulnar

3 Musketeers (C5, C6, C7)

2 Assassinations (C5, C6)

4 Mice (C6, C7, C8, T1)

5 Rats (C5, C6, C7, T1)

2 Unicorns (C8, T1)

Question 21

axilla region

Question 22

frozen should is also called

Answer 22

adhesive capsulitis

Question 23

RF for frozen shouklder

Answer 23

It most commonly affects people in middle age. Diabetes is a key risk factor.

Adhesive capsulitis can be:

• Primary – occurring spontaneously without any trigger
• Secondary – occurring in response to trauma, surgery or immobilisation

Question 24

pathophysiology of frozen should

Answer 24

inflammation and fibrosis in the joint capsule lead to adhesions (scar tissue). The adhesions bind the capsule and cause it to tighten around the joint, restrict movement in the joint

Question 25

presentation iof adhesive capsulitits

Answer 25

3 phases * **Painful phase** – ***shoulder pain*** is often the first symptom and may be worse at night * **Stiff phase** – ***shoulder stiffness*** develops and affects both active and passive movement (***external rotation*** is the most affected) – the pain settles during this phase * **Thawing phase** – there is a gradual improvement in stiffness and a return to normal can take 1-3 years before resolving

Question 26

investigations for frozen shoulder

Answer 26

* clinical diagnosis * x-ray normal * US, CT or MRI show thickened joint capsule

Question 27

management of frozen shoulder : conservative

Answer 27

* Continue using the arm but don’t exacerbate the pain * ***Analgesia*** (e.g., NSAIDs) * ***Physiotherapy*** * ***Intra-articular steroid injections*** * ***Hydrodilation*** (injecting fluid into the joint to stretch the capsule)

Question 28

management of frozen shoulder : surgical

Answer 28

* ***Manipulation under anaesthesia*** – forcefully stretching the capsule to improve the range of motion * ***Arthroscopy*** – keyhole surgery on the shoulder to cut the adhesions and release the shoulder

Question 29

**Subacromial impingement syndrome** (SAIS) r

Answer 29

inflammation and irritation of the rotator cuff tendons as they pass through the subacromial space, resulting in pain, weakness, and reduced range of motion within the shoulder.

Question 30

SAIS encompasses a **range of pathology** including

Answer 30

* rotator cuff tendinosis, * subacromial bursitis, * and calcific tendinitis. All these conditions result in an attrition between the coracoacromial arch and the supraspinatus tendon or subacromial bursa.

Question 31

RF for SAIS

Answer 31

\<35 years active or in manual professions

Question 32

common cause of SAIS

Answer 32

muscular weakness overuse of shoulder which cause the humerus to shift proximally towards the body

Question 33

presentation of SAIS

Answer 33

* progressive pain of anterior superior shoulder * exacerbated by abduction * **painful arc syndrome** * weakness/stiffness

Question 34

investigations for SAIS

Answer 34

* clinical * MRI imaging

Question 35

conservative management of SAIS

Answer 35

* analgesia * NSAIDS * physiotherapy * corticosteroid injections

Question 36

surgical intervetion for SAIS

Answer 36

If SAIS persists beyond **6 months without response to conservative management**, surgical intervention is recommended. Surgical intervention is particularly useful in patients with a reduced range of movement and is most commonly arthroscopic. Current surgical techniques include: * **Surgical repair of muscular tears**, most commonly the supraspinatus and long head of biceps tendon, resulting in an improvement in range of motion * **Surgical removal of the subacromial bursa**, a bursectomy, increasing the subacromial space and reducing pain * **Surgical removal of a section of the acromion**, an acriomioplasty, increasing the subacromial space and reducing pain

Question 37

complications of SAIS

Answer 37

**otator cuff degeneration** and tear, **adhesive capsulitis**, cuff tear arthropathy and complex regional pain syndrome.

Question 38

rotator cuff tears refers to

Answer 38

injury to the tendons of the rotator cuff muscles. The tendon may be partially or fully torn.

Question 39

causes of rotator cuff tears

Answer 39

due to an acute injury (e.g., a fall onto an outstretched hand) or degenerative changes with age. They may be related to overhead activities, such as playing tennis or overhead construction work.

Question 40

The rotator cuff is made of four muscles, each with a specific action at the shoulder (mnemonic is SITS):

Answer 40

* **S** – ***Supraspinatus*** – ***abducts*** the arm * **I** – ***Infraspinatus*** – ***externally rotates*** the arm * **T** – ***Teres minor*** – ***externally rotates*** the arm * **S** – **S*****ubscapularis***–***internally rotates*** the arm

Question 41

rotator cuff muscles tear

Answer 41

Shoulder pain Weakness and pain with specific movements relating to the site of the tear (e.g., abduction with a supraspinatus tear) disruption to sleep

Question 42

investigations for rotator cuff tears

Answer 42

X-ray not as useful US and MRI scan

Question 43

management of rotator cuff tears: non surgical option

Answer 43

particularly where they are at increased risk of complications from surgery * ***Rest*** and ***adapted activities*** * ***Analgesia*** (e.g., NSAIDs) * ***Physiotherapy***

Question 44

management of rotator cuff tears: surgical option

Answer 44

if young/active/ full-thickness tears * arthroscopic rotator cuff repair- tendon reattached to the bone during arthroscopy (keyhole surgery)

Question 45

shoulder disloacation

Answer 45

Shoulder ***dislocation*** is where the ball of the shoulder (***head of the humerus***) comes entirely out of the socket (***glenoid cavity of the scapula***).

Question 46

shoulder subluxation

Answer 46

partial dislocation of the shoulder. The ball does not come fully out of the socket and naturally pops back into place shortly afterwards.

Question 47

types of shoulder dislocation

Answer 47

* anterior dislocation (most common) * posterior * inferior

Question 48

anterior dislocation MOA

Answer 48

arm is forced ***backwards***(posteriorly) whilst ***abducted*** and ***extended*** at the shoulder. Picture someone reaching up and out to try and catch a heavy rock travelling towards them.

Question 49

posterior dislocation MOA

Answer 49

associated with electric shocks and seizures. ***TOM TIP: Exam questions might challenge you to distinguish between anterior and posterior dislocations. The answer is almost certainly an anterior dislocation unless the patient has had a seizure or an electric shock.***

Question 50

shoulder dislocation associated damage

Answer 50

* **Glenoid labrum tear** * Bankart lesions (anterior labrum)- due to repeated dislocation * Hill- Sach lesions * compression fractures of posterolateral part of the head of the humerus * anterior dislocation * **Axillary nerve damage**

Question 51

axillary nerve damage and shoulder dislocation

Answer 51

he axillary nerve comes from the ***C5*** and ***C6*** nerve roots. Damage causes a ***loss of sensation*** in the “***regimental badge***” area over the ***lateral deltoid***. It also leads to motor weakness in the ***deltoid*** and ***teres minor*** muscles.

Question 52

***Fractures*** can occur alongside shoulder dislocations, affecting the:

Answer 52

* ***Humeral head*** * ***Greater tuberosity*** of the ***humerus*** * ***Acromion*** of the ***scapula*** * ***Clavicle*** ***+ rotator cuff tears***

Question 53

which nevere is associated with anterior dislocations (KNOW FOR EXAM)

Answer 53

***Axillary nerve damage*** * ***loss of sensation*** in the “***regimental badge***” area over the ***lateral deltoid***.

Question 54

presentation of shoulder dislocation

Answer 54

* after acute injury * pain- muscles go into spasms and tighten around joint * will hold arm against side of body * deltoid flattened, head of humerus will cause a bulge and be palpable at the front of the shoulder

Question 55

what is important to assess patients with a shoulder dislocation forq

Answer 55

* Fractures * Vascular damage (e.g., absent pulses, prolonged capillary refill time and pallor) * Nerve damage (e.g., loss of sensation in the “regimental patch” area- axillary)

Question 56

special test for shoulder dislocation

Answer 56

apprehension test

Question 57

apprehension test

Answer 57

a special test to assess for ***shoulder instability***, specifically in the ***anterior direction***. It is likely to be positive after previous ***anterior dislocation*** or ***subluxation*** of the shoulder. This may be performed after recovery from any acute injuries. The patient lies supine. The shoulder is abducted to 90 degrees, and the elbow is flexed to 90 degrees. The shoulder is then slowly ***externally rotated*** in this position while watching the patient. As the arm approaches 90 degrees of external rotation, patients with shoulder instability will become anxious and apprehensive, worried that the shoulder will dislocate. **There is no pain associated with the movement, only apprehension.**

Question 58

investigations for shoulder dislocation

Answer 58

* x-ray * MRI- looking for bankarts and hill-sachs lesion and planning for surgery * arthroscopy- camera in shoulder to visualise structures

Question 59

dislocated shoulder should be…

Answer 59

ASAP shoulder relocation muscle spasm makes this harder over time, increasing risk of neurovascular injury during relocation

Question 60

Acute management of a shoulder dislocation involves:

Answer 60

* Analgesia, muscle relaxants and sedation as appropriate * Gas and air (e.g., Entonox) may be used, which contains a mixture of 50% nitrous oxide and 50% oxygen * A broad arm sling can be applied to support the arm * Closed reduction of the shoulder (after excluding fractures)- **kocher method** * Dislocations associated with a fracture may require surgery * Post-reduction x-rays * Immobilisation for a period after relocation of the shoulder

Question 61

ongoing management of shoulder dislocation

Answer 61

There is a high risk of ***recurrent dislocations***, particularly in younger patients. ***Physiotherapy*** is recommended to improve the function of the shoulder and reduce the risk of further dislocations. ***Shoulder stabilisation surgery*** may be required to improve stability and prevent further dislocations. This may be an arthroscopic or an open procedure. Underlying structural problems are corrected, such as: * Repairing Bankart lesions * Tightening the shoulder capsule * Bone graft using bone from the ***coracoid process*** to correct a bony injury to the glenoid rim (***Latarjet procedure***) * Correcting Hill-Sachs lesions (***Remplissage procedure***) There is a prolonged period of recovery and rehabilitation after shoulder stabilisation surgery (3 months or more).

Question 62

Erbs vs Klumpke palsy

Answer 62

brachial plexus injurys **Erbs** * upper brachial plexus injury * lateral traction of the neck- shoulder dystocia * waiters tip **Klumpke** * lower brachial plexus injury * e.g. grabbing a tree from above * total clawing of the hand