Elbow injuries
An adult who can fully straighten the elbow probably hasn't fractured it. Children need a lower threshold for X-ray.
A 7-year-old fell from a tree onto his outstretched hand. His elbow is swollen and deformed just above the joint. The radial pulse is weak, his hand is cool, and he can't make an "OK" sign with his thumb and index finger.
An hour later, a 35-year-old woman slipped onto her outstretched hand. She has tenderness over the outer elbow and pain on turning her forearm. She can't fully straighten the elbow. The X-ray shows a posterior fat pad but no fracture line.
What does each have, and which is the emergency?
- Neurovascular check firstRadial pulse, capillary refill, median (including the "OK" sign), ulnar and radial nerves. Document before and after any splint.
- Pulseless or white handOrthopaedics now. Gently straighten a little under analgesia and recheck.
- Adults: elbow extension testFull, equal extension makes a fracture unlikely.
- Children: low threshold for X-rayThe extension test isn't reliable.
- X-ray AP and lateralLook at fat pads and the alignment lines.
- Check the wrist and shoulderSame fall, other injuries (Monteggia, Essex-Lopresti).
- Splint and elevateCollar and cuff or back slab, per injury.
- Watch for compartment syndromeForearm pain on passive finger extension.
- Absent pulse, white or cool hand
- Nerve injury
- Displaced supracondylar fracture
- Open fracture
- Dislocation
- Forearm compartment syndrome
- Medial epicondyle fracture in a child
- Supracondylar fracture with brachial artery or nerve injury
- Medial epicondyle fragment trapped in the joint
- Monteggia fracture (ulna fracture with radial head dislocation)
- Lateral condyle fracture in a child
- Compartment syndrome
- Non-accidental injury in young children
- Pulled elbow mistaken for fracture (or the reverse)
| Posterior fat pad | Always abnormal: effusion from an occult fracture |
| Anterior fat pad raised ("sail sign") | Effusion, likely fracture |
| Supracondylar fracture | Commonest elbow fracture in children aged 5–7 |
| Anterior interosseous nerve | Can't make an "OK" sign (flex thumb and index tips) |
| Radial head fracture (adult, undisplaced) | Sling for comfort a few days, early movement |
| Elbow dislocation | Reduce early, check ulnar and median nerves before and after |
| Paracetamol | 1 g 4 times daily (adult) |
| Ibuprofen | 400 mg 3 times daily with food (adult) |
Check every dose against a current drug reference and your hospital protocol.
On this page
History
- Mechanism: fall on the outstretched hand (supracondylar in children, radial head in adults), fall on the point of the elbow (olecranon), pulled by the arm (pulled elbow in toddlers).
- Tingling, numbness, weakness in the hand.
- Wrist or shoulder pain from the same fall.
- In young children: does the story fit? Delay? Other injuries?
Examination
- LookSwelling, deformity, bruising, wounds, carrying angle.
- FeelRadial head (lateral, turn the forearm), olecranon, medial and lateral epicondyles, supracondylar ridge. Wrist and shoulder too.
- MoveElbow extension test in adults; forearm rotation.
- NervesMedian (thumb opposition, sensation over index finger), anterior interosseous ("OK" sign), ulnar (finger spreading, little finger sensation), radial (wrist and finger extension, back of thumb web).
- CirculationRadial pulse, capillary refill, colour, temperature.
Elbow extension test (adults)
- Ask the patient to straighten both elbows fully.
- Full, equal extension: a fracture is unlikely; treat as soft tissue with follow-up if not better.
- Can't fully extend: X-ray.
- Not reliable in children: X-ray injured children with a low threshold.
Reading the elbow X-ray
- Fat padsA small anterior fat pad is normal. A raised anterior "sail" or any visible posterior fat pad means blood in the joint: treat as a fracture.
- Anterior humeral lineShould pass through the middle third of the capitellum. Passing in front of it: supracondylar fracture with backward displacement.
- Radiocapitellar lineShould pass through the capitellum on every view. If not: radial head dislocation (look for an ulna fracture: Monteggia).
- Ossification centres (children)Appear in order: Capitellum, Radial head, Internal (medial) epicondyle, Trochlea, Olecranon, External (lateral) epicondyle. If the trochlea is visible but the medial epicondyle isn't in its place, it may be trapped in the joint.
Which injury?
| Injury | Who | Clues | Management |
|---|---|---|---|
| Supracondylar fracture | Children 5–7 | Fall on outstretched hand, swelling above the elbow | Undisplaced: collar and cuff or back slab; displaced: theatre |
| Radial head fracture | Adults | Lateral tenderness, pain on forearm rotation, fat pad | Undisplaced: sling, early movement |
| Olecranon fracture | Any | Fall on the point of the elbow, can't extend against gravity | Often surgery if displaced |
| Elbow dislocation | Adults and children | Deformity, can't move | Urgent reduction, check nerves |
| Lateral condyle fracture | Children | Lateral swelling | Needs fixation if displaced |
| Medial epicondyle fracture | Children and teenagers | Medial swelling, after dislocation | Fragment may be trapped: orthopaedics |
| Monteggia | Any | Ulna fracture with radial head dislocation | Orthopaedics |
| Pulled elbow | Toddlers | Pulled by the arm, no swelling | Reduce; see pulled elbow |
Supracondylar fracture in a child
- Emergency: orthopaedics now
- gently straighten slightly under analgesia, recheck
- theatre
- Urgent orthopaedics
- back slab in comfortable position
- elevate
- nerve checks
- Collar and cuff or above-elbow back slab
- fracture clinic in a week
- The anterior interosseous nerve (branch of the median nerve) is most often injured: the child can't flex the tips of the thumb and index finger to make an "OK" sign.
- Radial and ulnar nerves can also be injured, especially after surgery.
- Watch for compartment syndrome in the forearm: pain out of proportion, pain on passive finger extension.
Treatment
- Undisplaced radial head fracture or fat pad sign in adults: sling for comfort for a few days, then early active movement. Stiffness is the main risk of keeping it still too long.
- Displaced fractures and dislocations: orthopaedics.
- Elbow dislocation: reduce early under analgesia or sedation; check nerves and pulses before and after; X-ray after; back slab.
Common mistakes
- Not testing the "OK" sign in a child with a supracondylar fracture.
- Ignoring a posterior fat pad because no fracture line is visible.
- Keeping an adult radial head fracture immobilised for weeks.
- Missing a radial head dislocation with an ulna fracture (Monteggia).
- Missing a trapped medial epicondyle in a child.
- Not thinking about non-accidental injury in a toddler with a fracture.
Frequently asked questions
What does a posterior fat pad on an elbow X-ray mean?
Blood in the joint from a fracture (usually the radial head in adults, supracondylar in children), even if no fracture line is seen. Treat it as a fracture.
Which nerve is most often injured in a supracondylar fracture?
The anterior interosseous branch of the median nerve: the child can't make an "OK" sign with the thumb and index finger.
How is an undisplaced radial head fracture treated?
A sling for comfort for a few days and early active movement to prevent stiffness, with fracture clinic follow-up.
What is the elbow extension test?
In adults, if both elbows straighten fully and equally after injury, a fracture is unlikely. If not, X-ray. It is not reliable in children.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. An adult's elbow X-ray after a fall shows a posterior fat pad but no fracture line. What is the likely injury?
Answer: Occult radial head fracture. Treat as a radial head fracture: sling and early movement.
- Ligament sprain only: Fat pad suggests fracture.
- Normal X-ray: A posterior fat pad is always abnormal.
- Olecranon bursitis: No.
- Dislocation: Would be visible.
2. A child with a supracondylar fracture can't make an "OK" sign. Which nerve is injured?
Answer: Anterior interosseous nerve. The anterior interosseous branch of the median nerve supplies FPL and FDP to the index finger.
- Axillary nerve: Shoulder.
- Musculocutaneous nerve: Elbow flexion.
- Radial nerve: Wrist drop.
- Ulnar nerve: Causes clawing and finger abduction weakness.
3. A child's supracondylar fracture has an absent radial pulse and a white hand. What is needed?
Answer: Urgent orthopaedic reduction. A pulseless pale hand needs urgent reduction; the brachial artery may be compressed.
- Ultrasound next week: No.
- Plaster cast only: Not enough.
- Collar and cuff and review tomorrow: Limb at risk.
- Physiotherapy: No.
4. After a displaced extension-type supracondylar fracture, a 6-year-old cannot make an ‘OK’ sign (can’t flex the thumb IP and index DIP joints). Which nerve is injured?
Answer: Anterior interosseous. Supracondylar humerus fractures (FOOSH in children 5–7): extension type most common. Nerve injury: anterior interosseous (branch of median; most common in extension type) — weak FPL and FDP index (can’t make OK sign, no sensory loss); radial nerve; ulnar (flexion type, iatrogenic from medial pins). Brachial artery injury (pink pulseless/white hand), compartment syndrome → Volkmann ischaemic contracture. Treat displaced fractures with closed reduction and percutaneous pinning.
- Superficial radial nerve: Superficial radial nerve injury affects sensation, not the OK sign.
- Ulnar nerve: Ulnar injury follows flexion-type fractures and affects the little finger.
- Axillary nerve injury: The axillary nerve supplies the shoulder.
5. A woman fell onto her elbow; she cannot actively extend the elbow against gravity and X-ray shows a displaced transverse olecranon fracture. What is the treatment?
Answer: Open reduction and tension-band wiring. Olecranon fracture: direct fall onto the elbow or triceps avulsion; displaced fractures disrupt the extensor mechanism (can’t extend against gravity) → ORIF (tension-band wiring for simple transverse; plate for comminuted); undisplaced with intact extension → conservative. Elderly low-demand patients may be managed non-operatively. Ulnar nerve lies nearby (behind medial epicondyle). Radial head fractures: FOOSH, pain on rotation, fat pad sign.
- Collar and cuff only: A displaced olecranon fracture with lost extension needs fixation.
- Closed reduction and cast in extension: The fracture is unstable.
- Excision of radial head: The radial head is the wrong bone.
6. After a supracondylar fracture of the humerus, a child cannot flex the index finger when making a fist (pointing index, 'hand of benediction') and the thenar muscles are weak. Which nerve is injured?
Answer: Median nerve at the elbow. A median nerve injury at the elbow paralyses the forearm flexors it supplies (FDS, lateral FDP, FPL) and thenar muscles. On making a fist, the index (and middle) finger stays straight. Injury at the wrist (carpal tunnel) spares forearm flexors, causing only thenar weakness and sensory loss. Supracondylar fractures also risk the brachial artery (Volkmann's contracture).
- Ulnar nerve at the elbow: Clawing of ring and little fingers.
- Radial nerve in the spiral groove: Wrist drop.
- Median nerve at the wrist only: Spares the long finger flexors.
- Musculocutaneous nerve: Weak elbow flexion.
7. A child falls on an outstretched hand and sustains a displaced supracondylar fracture of the humerus. Which artery is most at risk?
Answer: Brachial artery. Displaced extension-type supracondylar fractures can tear or compress the brachial artery (and median/anterior interosseous nerve; also radial nerve). Untreated ischaemia causes forearm compartment syndrome and Volkmann's ischaemic contracture of the flexors. Check the radial pulse and capillary refill; urgent reduction is needed if the hand is pulseless.
- Radial artery at the wrist: Distal, not at the fracture.
- Axillary artery: Proximal.
- Profunda brachii artery: Runs with the radial nerve in the spiral groove.
- Ulnar artery at the wrist: Distal.
References and dose sources
- NICE NG38 — Fractures (non-complex)
- Appelboam et al., BMJ 2008 — Elbow extension test
- Paracetamol dosing: Drugs.com: Acetaminophen (paracetamol) dosage (see also our paracetamol dose page)
- Ibuprofen dosing: Drugs.com: Ibuprofen dosage (see also our ibuprofen dose page)
- Morphine dosing: Drugs.com: Morphine dosage (see also our morphine dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.