Shoulder US

Question 1

Define echogenic and its synonyms

Answer 1

Echogenic: Produces lots of echoes

Synonyms: White, bright, hyperechoic

Hyperechoic: Relative term describing structures producing more echoes, appearing bright or white (genic = producing/forming)

Question 2

Define echolucent and its related terms.

Answer 2

Echolucent: Produces few echoes, appears dark gray

Hypoechoic: Relative term describing structures producing fewer echoes

Echopenic: From “penia” meaning deficiency

Question 3

Define anechoic and its characteristics

Answer 3

Anechoic: No echoes, without internal echoes

Synonyms: Echo-free

Appearance: Homogeneous

Typical structures: Fluid or cystic structures

Question 4

What is the difference between homogeneous and heterogeneous?

Answer 4

• Homogeneous: Uniform echo pattern throughout
• Heterogeneous: Mixed echo pattern with varying echogenicity

Question 5

What are the key advantages of musculoskeletal ultrasound?

Answer 5

Allows dynamic assessment of joints, muscles, tendons, nerves, and ligaments

Body parts assessed: Shoulder, elbow, wrist, hand, hip, thigh, knee, ankle, foot

Real-time imaging capability

Non-ionizing radiation

Cost-effective and readily available

Question 6

What is the fundamental trade-off in ultrasound frequency selection?

Answer 6

Higher frequency = Better resolution BUT less depth penetration

Transducer selection based on depth of target structures

Patient size affects frequency choice

Question 7

What are the specific transducer frequencies and their applications?

Answer 7

Linear array 7-17 MHz or higher: Superficial structures (finger/toe tendons)

Linear array 5-12 MHz: Deeper structures (hip, shoulder)

Curved array 1-5 MHz: Large patients or deep muscles/tendons

High frequency probe: Hockey stick design

Stand-off pad: May be required for very superficial structures

Question 8

What are the key technical considerations for MSK ultrasound?

Answer 8

Dynamic scanning: Real-time assessment during movement

Contralateral comparison: Often necessary for accurate diagnosis

Frequency selection: Based on patient size and structure depth

Question 9

Describe the normal ultrasonic appearance of muscles.

Answer 9

Echogenicity: Relatively hypoechoic

Internal structure: Echogenic fibrils

Covering: Echogenic fascia

Function: Contractile tissues that move body parts or alter internal organ shape

Question 10

Describe the normal ultrasonic appearance of tendons.

Answer 10

Echogenicity: Hyperechoic

Pattern: Striated appearance (depends on ultrasound beam angle)

Protection: Tendons subjected to friction have synovial sheath or peri-tendon

Vascularity: Sparse vascular network

Question 11

How do bony structures appear on ultrasound?

Answer 11

Echogenicity: Echogenic surface

Characteristic feature: Posterior acoustic shadowing

Question 12

What are the three types of muscle and their characteristics?

Answer 12

Skeletal muscle: Voluntary, moves bones at joints

Involuntary muscle: Smooth muscle

Cardiac muscle: Heart muscle

Question 13

What are the major functions of skeletal muscle?

Answer 13

• Movement
• Posture maintenance
• Joint stabilization
• Attachment: Connected to bones via connective tissue

Question 14

Describe the ultrasonic appearance of muscle tears.

Answer 14

Pattern disruption: Loss of organized fibrillar pattern

Echogenicity: Hypoechoic areas with loss of normal echogenic perimysium

Larger injuries: Fluid-containing regions of hematoma or seroma with surrounding frayed muscle ends

Question 15

What is the anatomical definition and characteristics of tendons?

Answer 15

Definition: Band of tough, inelastic fibrous tissue

Function: Connects muscle to bony attachment

Protection: Some enclosed in self-lubricating sheaths against friction

Friction adaptation: Synovial sheath or peri-tendon for high-friction areas

Question 16

Describe tendinitis/tenosynovitis characteristics.

Answer 16

Cause: Inflammation due to age-related elasticity loss or acute trauma

Symptoms: Pain and decreased range of movement

Complications: Delayed treatment may lead to rupture

Sonographic appearance:
- Focal or diffuse decreased echogenicity within tendon fibers
- Increased fluid in synovial sheath
- Hyperemia (increased Doppler flow)

Question 17

What are the ultrasonic features of tendon tears?

Answer 17

Clefts: Anechoic or hypoechoic areas within tendon

Continuity loss: Loss of fibrillar pattern continuity or absence of tendon fibers

Associated findings: Fluid often detected in tendon sheath and/or bursa

Question 18

Describe ligament characteristics and pathology.

Answer 18

Characteristics:
- Connect bone to bone at joints
- Inelastic, composed of collagen fibers
- Prevent excessive joint motion
- Flexible but cannot be stretched

Pathology:
- Excessive joint force causes ligament injury
- Slow healing due to poor blood supply

Question 19

Describe nerve characteristics and damage symptoms

Answer 19

Characteristics:
- Soft, flexible structures
- Shape changes from round to oval depending on pathway

Damage causes: Injury, swelling, infection, disease

Symptoms: Referred pain, numbness, weakness, paralysis

Question 20

What are bursae and their ultrasonic appearance?

Answer 20

Definition: Sac-like structures containing fluid around friction areas (between bone and tendon)

Normal appearance:
- Most bursae collapsed and difficult to identify
- Some have small amount of hypoechoic fluid separating hyperechoic bursal walls

Bursitis appearance:
- Thickened bursa becomes visible
- Clinical presentation: Pain, especially with movement

Question 21

What should be considered regarding bone fractures on ultrasound?

Answer 21

Detection: May be seen incidentally

Protocol: If suspected, X-ray first

Example: Greater tuberosity fracture found during rotator cuff examination

Importance: Clinical management differs significantly from rotator cuff tear

Question 22

Define and differentiate Baker’s cyst and ganglion cysts.

Answer 22

Baker’s Cyst:
- Popliteal cyst (fluid-filled sac behind knee)
- Cause: Joint injury or synovial lining inflammation
- Mechanism: Synovial fluid leaking from joint

Ganglion:
- Non-cancerous cyst with thick, jelly-like fluid
- Location: Most commonly hand or wrist
- Cause: Repeated injuries irritating tendon membrane, causing fluid leak and sac formation

Question 23

What are the advantages of shoulder ultrasound?

Answer 23

• Established modality: Well-accepted for shoulder structure evaluation
• Applications: Rotator cuff diseases, non-rotator cuff abnormalities
• Accuracy: 91-100% for partial and full-thickness rotator cuff tears
• Comparison: As accurate as MRI in experienced hands
• Benefits: Cheap, readily available, high-resolution, no ionizing radiation
• Dynamic capability: Real-time evaluation during movement

Question 24

What conditions can shoulder ultrasound evaluate?

Answer 24

Rotator cuff diseases:
- Tendon tears
- Tendinitis
- Bursitis

Non-rotator cuff abnormalities:
- Instability problems
- Synovial joint diseases
- Nerve entrapment syndromes

Question 25

What are the requirements for effective shoulder ultrasound?

Answer 25

Standardized imaging protocol: Essential for exhaustive and efficient examination Knowledge of pitfalls: Essential when examining structures Experience: Critical for diagnostic accuracy

Question 26

What are the 5 tendons assessed in rotator cuff evaluation? (Remember using your 5 fingers)

Answer 26

1. Biceps tendon (long head and short head) 2. Subscapularis tendon 3. Supraspinatus tendon 4. Infraspinatus tendon 5. Teres minor

Question 27

What is anisotropy artifact and its effects?

Answer 27

Definition: Artifact occurring when imaging with oblique ultrasound beam instead of perpendicular beam Effects on tendon appearance: - Decreased echogenicity - Loss of tendon surface definition - Lack of delineation of fibrillar internal architecture Cause: Area losing signal because beam isn't at 90 degrees

Question 28

Define shoulder impingement and its characteristics.

Answer 28

Definition: Painful upper extremity condition from structural subacromial space narrowing, tendonitis, or bursitis Diagnosis: Primarily by history and physical examination Treatment approach: - Early identification before degenerative changes - Physical therapy exercises to strengthen shoulder girdle - Pharmacological interventions to decrease inflammation

Question 29

What are the differential diagnoses for shoulder impingement?

Answer 29

- Adhesive capsulitis - Rotator cuff tear - Acromioclavicular joint arthritis - Acromioclavicular joint sprain - Trapezius muscle spasm - Biceps tendonitis - Biceps tendon rupture - Calcific tendonitis - Glenohumeral arthritis - Distal clavicle osteolysis - Cervical radiculopathy - Thoracic outlet syndrome Note: Hard to diagnose, so X-ray first is much easier

Question 30

Describe the impingement maneuver test.

Answer 30

Type: Dynamic test for impingement Normal response: No impingement of bursa Positive test: When patient abducts arm, bursa bunches up and causes pain

Question 31

Define frozen shoulder and its clinical course.

Answer 31

Alternative name: Adhesive capsulitis Characteristics: Stiffness and pain in shoulder joint Onset: Signs and symptoms begin slowly, worsen, then improve Duration: Usually resolves within 1-3 years

Question 32

What are the treatment options for frozen shoulder?

Answer 32

Range-of-motion exercises Injections: Corticosteroids and numbing medications into joint Surgery: Rarely, arthroscopic surgery to loosen joint capsule for improved mobility

Question 33

Describe the three stages of frozen shoulder.

Answer 33

Stage 1 - Freezing (2-9 months): Any shoulder movement causes pain Progressive limitation of shoulder mobility Stage 2 - Frozen (4-12 months): Pain might lessen Shoulder becomes stiffer Movement becomes more difficult Stage 3 - Thawing (5-24 months): Shoulder mobility begins to improve Gradual return of function

Question 34

Why is understanding ultrasound appearances important for diagnosis?

Answer 34

- Normal structures: Have predictable echogenic patterns - Pathological changes: Alter normal echo patterns - Dynamic assessment: Allows real-time evaluation during movement - Comparison: Contralateral comparison helps identify abnormalities - Cost-effectiveness: Non-invasive, readily available diagnostic tool

Question 35

What factors influence the choice of ultrasound technique?

Answer 35

- Patient factors: Size, muscle mass, body habitus - Target structure: Depth, size, location - Clinical question: Static vs. dynamic assessment needed - Operator experience: Critical for accurate interpretation - Equipment available: Transducer types and frequencies