Upper Limb X-Ray

Upper limb radiography images the shoulder girdle (clavicle, scapula, acromioclavicular and glenohumeral joints), humerus, elbow, forearm, wrist, hand and fingers.

Every area needs at least two views at right angles.

• Shoulder (anteroposterior, plus an axillary or scapular Y view, because a single view misses dislocation).
• Clavicle (anteroposterior and a 15-degree cephalic tilt).
• Humerus (anteroposterior and lateral).
• Elbow (anteroposterior and a true lateral with the elbow flexed 90 degrees).
• Forearm (anteroposterior and lateral including both the elbow and wrist, because forearm fractures are frequently paired with a joint injury).
• Wrist (posteroanterior and lateral, with a scaphoid series of posteroanterior with ulnar deviation, oblique and lateral when scaphoid fracture is suspected).
• Hand (posteroanterior, oblique and lateral, with a true lateral for each finger).

The dose is very small (0.001 to 0.01 mSv for a limb view), and the examination is among the most frequently performed in emergency departments.

Fractures of the distal radius, scaphoid, clavicle, proximal humerus, forearm bones and hand account for a large share of limb injuries. Radiographs are used to diagnose, classify and plan treatment of fractures and dislocations, to detect joint disease (osteoarthritis, rheumatoid arthritis, gout, psoriatic arthritis), infection, tumours, metabolic bone disease, and foreign bodies.

For occult injuries (scaphoid, radial head and supracondylar fractures), initial films can be normal, and follow up films or MRI are needed. Ultrasound is increasingly used for paediatric forearm fractures and for tendon and soft tissue injury.

Indications. Injury with bone tenderness, deformity, swelling, loss of function or inability to bear weight through the limb. Suspected dislocation. Suspected scaphoid fracture (snuffbox tenderness). Joint pain, stiffness or swelling (arthropathy, crystal disease, infection). Bone pain with fever, or a mass. Suspected foreign body. Suspected non-accidental injury in a child.

Metabolic bone disease. Post-operative and fracture healing review. Not for minor soft tissue injury without bony tenderness, or for routine imaging of mild chronic joint pain.

Contraindications and precautions. No absolute contraindication. Pregnancy: the dose to the foetus from limb films is negligible. Remove jewellery, watches and clothing from the field, and splints that obscure bone detail where this is safe. Provide analgesia and support the injured limb for positioning; for a suspected unstable injury use the views that need the least manipulation. Document neurovascular status before and after imaging.

Preparation and technique. Include the joint on each side of a long bone fracture. For the elbow lateral, keep the arm flexed to 90 degrees with the thumb up. Use true lateral and posteroanterior positioning, because oblique projections hide displacement. In children, compare with the opposite side or use growth plate knowledge, and use a minimum number of views with immobilisation.

Normal appearances. Smooth cortical outlines with uniform trabecular patterns, regular joint spaces and congruent articular surfaces.

Elbow: the anterior humeral line (along the anterior cortex of the humerus on the lateral view) passes through the middle third of the capitellum, and the radiocapitellar line (along the radial neck) passes through the centre of the capitellum on every view. A small anterior fat pad may be seen, but a posterior fat pad is not visible.

Wrist: three smooth carpal arcs (Gilula arcs), a scapholunate gap of under 3 mm, and a radial inclination of about 22 degrees with 11 degrees of palmar tilt. Children: growth plates, ossification centres (in a predictable order at the elbow, "CRITOE": capitellum, radial head, internal epicondyle, trochlea, olecranon, external epicondyle) and cartilage that is not visible.

Interpretation. Describe a fracture by site, pattern (transverse, oblique, spiral, comminuted), displacement, angulation, shortening, joint involvement, and whether it is open.

• Shoulder: anterior dislocation (about 95%), the humeral head lying under the coracoid process, with a Hill-Sachs defect (impaction of the posterolateral humeral head) and a Bankart lesion (glenoid rim fracture).
• Posterior dislocation is subtle on an anteroposterior view: the "light bulb" sign (humeral head in fixed internal rotation), loss of the normal overlap of head and glenoid, and a trough sign; an axillary view confirms it.
• Proximal humerus fractures are described by the number of displaced parts (head, shaft, and greater and lesser tuberosities).
• Acromioclavicular separation is graded by the coracoclavicular distance (a rise of 25 to 100% over the normal side).
• Clavicle: mid-shaft fractures are commonest (about 80%), with shortening and displacement; lateral fractures may disrupt the coracoclavicular ligaments; medial fractures or sternoclavicular dislocation need CT.
• Elbow: a posterior fat pad sign or an elevated anterior fat pad ("sail" sign) indicates an elbow joint effusion and an occult fracture until proved otherwise (radial head in adults, supracondylar in children).
• Disruption of the anterior humeral line indicates a supracondylar fracture.
• Monteggia fracture (ulnar fracture with radial head dislocation) and Galeazzi fracture (radial shaft fracture with distal radio ulnar joint dislocation) show a paired injury, so a lone forearm fracture without joint is rare.
• Children: Salter-Harris physeal injuries (I through the physis, II through the physis and metaphysis, III through the physis and epiphysis, IV through the metaphysis, physis and epiphysis, V crush).
• Buckle (torus) fractures of the distal radius, greenstick fractures, and plastic bowing.
• Supracondylar fractures are the commonest elbow fractures. Lateral condyle fractures are unstable and commonly missed.
• Wrist: Colles fracture (distal radius, dorsal angulation), Smith fracture (volar angulation) and Barton fracture (intra-articular rim fracture with carpal subluxation). Ulnar styloid fractures are common.
• Scaphoid fracture (waist about 70%) may not be visible on initial films in 10 to 20%, so a suspected fracture is immobilised and reviewed by repeat films at 10 to 14 days or by early MRI.
• Scapholunate dissociation (a gap over 3 mm, the "Terry Thomas" sign, and a "signet ring" scaphoid), lunate dislocation (a triangular "piece of pie" lunate on the lateral film and a "spilled teacup" sign) and perilunate dislocation need urgent orthopaedic review.
• Hand: metacarpal neck ("boxer") fractures, Bennett and Rolando fractures at the thumb base, phalangeal fractures, and mallet injury with avulsion of the distal phalanx.
• Arthritis: osteoarthritis (joint space narrowing, osteophytes, sclerosis, cysts; distal interphalangeal "Heberden" and first carpometacarpal involvement).
• Rheumatoid arthritis (periarticular osteopenia, marginal erosions, symmetrical metacarpophalangeal and wrist involvement, ulnar styloid erosions).
• Gout (punched out erosions with overhanging edges, tophi) and calcium pyrophosphate deposition (chondrocalcinosis, triangular fibrocartilage and the scapholunate joint).
• Psoriatic arthritis ("pencil in cup" deformity, periostitis, dactylitis, distal involvement).
• Infection and tumour: osteomyelitis (soft tissue swelling, periosteal reaction and lucency, appearing 7 to 14 days after onset), septic arthritis (effusion, later joint destruction), benign lesions (enchondroma, bone cyst), and malignant lesions (permeative destruction, Codman triangle, sunburst periosteal reaction, soft tissue mass).
• Calcific tendinitis of the shoulder (calcific density near the greater tuberosity), osteonecrosis (humeral head, lunate in Kienböck disease, scaphoid), and metabolic bone disease (osteopenia, subperiosteal resorption of the radial middle phalanges in hyperparathyroidism, rickets).
• Foreign bodies: metal and glass are visible, and wood and plastic are not.

Critical values and findings needing immediate action.

• Open fracture (wound communicating with the fracture): antibiotics, tetanus prophylaxis, irrigation, splintage and orthopaedic surgery within hours.
• Displaced supracondylar fracture with absent radial pulse, cold hand or nerve palsy, or a fracture dislocation with neurovascular compromise: urgent reduction and vascular assessment.
• Suspected compartment syndrome (pain out of proportion, pain on passive stretch, tense swelling) after forearm or elbow fractures: emergency fasciotomy, not further imaging.
• Unreduced shoulder, elbow, lunate or perilunate dislocation: urgent reduction under sedation or anaesthesia.
• Clinically suspected scaphoid fracture with normal films: immobilise and arrange further imaging (avascular necrosis risk with delayed diagnosis).
• Multiple fractures of different ages, metaphyseal corner fractures, rib fractures or implausible history in a child: safeguarding referral and skeletal survey.
• Septic arthritis or osteomyelitis (fever, hot joint, raised inflammatory markers): urgent aspiration or surgical washout and antibiotics.
• Pathological fracture or aggressive lesion: urgent bone tumour review with staging imaging.

Limitations and artefacts.

• Single views miss fractures and dislocations (posterior shoulder dislocation is missed on an isolated anteroposterior view in up to half of cases).
• Initial films miss 2 to 10% of fractures (scaphoid, radial head, undisplaced and buckle fractures, stress fractures); repeat films or MRI follow when clinical suspicion persists.
• Normal variants mimic fractures: accessory ossicles, bipartite bones, growth plates, nutrient canals, sesamoids and the os centrale.
• Children's cartilage covered epiphyses hide articular injuries, and ossification centres appear at different ages; comparison views or ultrasound help.
• Overlying plaster, splints, dressings and jewellery reduce quality.
• A fracture found must not stop the search for a second injury (calcaneus and spine in falls, ulna and radial head with forearm fractures).
• Fracture healing is assessed by callus and loss of the fracture line, with radiographic union lagging clinical union; radiographs are not repeated more often than the management requires.
• Interobserver differences arise in classification, and measurements of angulation depend on positioning.

Special groups.

• Children: the commonest injuries are buckle and greenstick fractures, supracondylar and physeal fractures; consider non-accidental injury in infants and when history does not match the injury.
• Older adults: low energy distal radius, proximal humerus and hip fractures reflect osteoporosis and indicate need for bone density assessment.
• Patients with rheumatoid arthritis: cervical spine and atlanto axial involvement affect anaesthesia.
• Patients with diabetes or neuropathy: neuropathic (Charcot) joints at the wrist and shoulder in syringomyelia.
• Athletes: stress fractures of the metacarpals, ulna and clavicle, and physeal injuries in young gymnasts.
• Regions: trauma from falls, road traffic injuries and assault dominates; traditional bone setter treatment can produce delayed presentations with malunion, infection or gangrene, and osteomyelitis in children and sickle cell dactylitis ("hand foot syndrome") are common.

Follow up tests. Repeat films after 10 to 14 days for suspected occult fracture. MRI for scaphoid, occult fractures, ligament and tendon injury, and early osteomyelitis, CT for complex intra-articular fractures and fracture healing, ultrasound for soft tissue injury, tendon rupture, effusion and paediatric fractures. Also arrange bone scintigraphy, inflammatory markers, uric acid.

Further tests: rheumatoid factor and anti-citrullinated peptide antibodies, joint aspiration with crystal analysis and culture, bone density scan, and orthopaedic or hand surgery review.