Opacitis archive
Every past scan, with the diagnosis, the findings and a pearl. Newest first.
12 past puzzles, up to Thursday 5 November 2026. Today’s and future puzzles are never shown here.
November 2026
#12 · Thursday 5 November 2026 Medium
Source page by James Heilman, MD · CC BY-SA 4.0 · via Wikimedia Commons A child's elbow
A 7-year-old fell off the monkey bars onto an outstretched hand and won't move the elbow.
Answer: Supracondylar fracture of the humerus
Why: A fracture across the lower humerus just above the condyles, with some displacement of the lower fragment.
Pearl: The commonest elbow fracture in children. Always check the radial pulse and nerves (especially the anterior interosseous nerve: ask for an 'OK' sign). A raised posterior fat pad suggests a hidden fracture.
Play this puzzle#11 · Wednesday 4 November 2026 Medium
Source page by Nevit Dilmen · CC BY-SA 3.0 · via Wikimedia Commons Recurrent infections
A 58-year-old woman has had repeated urinary infections and loin aches. Plain X-ray of the abdomen:
Answer: Staghorn calculus
Why: A large, branching radio-opaque stone filling the renal pelvis and calyces of one kidney, shaped like a stag's antlers.
Pearl: Staghorn calculi are usually infection stones and can destroy the kidney if left. They usually need removal (often percutaneous nephrolithotomy) plus treatment of the infection.
Play this puzzle#10 · Tuesday 3 November 2026 Easy
Source page by Lucien Monfils · CC BY-SA 4.0 · via Wikimedia Commons A fall on the hand
A 72-year-old woman slipped on wet tiles and landed on her outstretched hand. Her wrist looks like a dinner fork.
Answer: Colles fracture
Why: A fracture of the distal radius with the broken fragment angled backwards (dorsally): the 'dinner fork' deformity of a Colles fracture.
Pearl: A low-energy wrist fracture in an older person is often the first sign of osteoporosis, so consider bone density testing. A Smith fracture tips the other way (forwards).
Play this puzzle#9 · Monday 2 November 2026 Easy
Source page by Basem Abbas Al Ubaidi · CC BY 4.0 · via Wikimedia Commons Dull on one side
A 41-year-old with weeks of cough, night sweats and weight loss is now breathless. One lung base is dull to percussion.
Answer: Pleural effusion
Why: A dense white opacity at the left base with a curved upper edge rising towards the side wall (meniscus sign), obscuring the diaphragm: a pleural effusion, here from tuberculosis.
Pearl: Tap it if you don't know why it's there. Light's criteria separate exudates from transudates. In many countries, TB is a leading cause of exudative effusion in young adults.
Play this puzzle#8 · Sunday 1 November 2026 Genius
Source page by Stevenfruitsmaak · CC BY-SA 3.0 · via Wikimedia Commons A stiff back
A 38-year-old man has had years of morning back stiffness that eases with exercise. He also had a red, painful eye last year.
Answer: Ankylosing spondylitis
Why: Thin, smooth bony bridges (syndesmophytes) join the vertebrae into a continuous column: a 'bamboo spine'.
Pearl: Inflammatory back pain improves with exercise and is worse with rest and in the early morning. Treat early: modern biologics can prevent fusion.
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October 2026
#7 · Saturday 31 October 2026 Hard
Source page by Mohamed Jarraya, Daichi Hayashi, Frank W. Roemer, Michel D. Crema, Luis Diaz, Jane Conlin, Monica D. Marra, Nabil Jomaah, and Ali Guermazi · CC BY 3.0 · via Wikimedia Commons Sore wrist after a fall
A 26-year-old has wrist pain after a fall. He is tender in the anatomical snuffbox.
Answer: Scaphoid fracture
Why: A faint lucent line across the waist of the scaphoid: a subtle scaphoid fracture.
Pearl: Scaphoid fractures are often invisible on the first X-ray. If you suspect one, immobilise and arrange repeat imaging or MRI, because missed fractures can lead to avascular necrosis.
Play this puzzle#6 · Friday 30 October 2026 Hard
Source page by Mont4nha · CC0 · via Wikimedia Commons A hugely swollen belly
A child with chronic constipation has severe abdominal distension and pain. Abdominal X-ray:
Answer: Sigmoid volvulus
Why: A massively distended, inverted-U loop of large bowel rising out of the pelvis: the 'coffee bean' sign of a twisted sigmoid colon.
Pearl: Sigmoid volvulus can often be untwisted with a flexible sigmoidoscope and rectal tube; recurrence is common, so surgery is usually planned afterwards.
Play this puzzle#5 · Thursday 29 October 2026 Medium
Source page by Hellerhoff · CC BY-SA 3.0 · via Wikimedia Commons A punch gone wrong
A 23-year-old has a swollen hand with a sunken knuckle after punching a wall.
Answer: Fifth metacarpal neck fracture (boxer's fracture)
Why: A fracture through the neck of the fifth metacarpal with the head tipped towards the palm: a boxer's fracture.
Pearl: Any skin break over the knuckle after a punch is a human bite until proven otherwise: it needs washout and antibiotics.
Play this puzzle#4 · Wednesday 28 October 2026 Medium
Source page by Benjamín Herreros, Isabel Plaza, Rebeca García, Marta Chichón, Carmen Guerrero and Emilio Pintor · CC BY 4.0 · via Wikimedia Commons Fever that won't settle
An 82-year-old woman has had fevers, chills and weight loss for two weeks. She is on long-term steroids.
Answer: Miliary tuberculosis
Why: Countless tiny (1–3 mm) nodules evenly scattered through both lungs: a 'millet seed' pattern from blood-borne spread of TB.
Pearl: The chest X-ray can be normal early in miliary TB. Look for TB elsewhere, including the meninges, and check HIV status.
Play this puzzle#3 · Tuesday 27 October 2026 Easy
Source page by Drfrancescsoler · CC BY-SA 4.0 · via Wikimedia Commons A fall on the shoulder
A 35-year-old fell while skiing. His shoulder looks squared off and he holds his arm away from his body.
Answer: Anterior shoulder dislocation
Why: The humeral head lies below and in front of the glenoid instead of within it: anterior dislocation of the shoulder.
Pearl: Check the axillary nerve (sensation over the 'regimental badge' area) before and after reduction. Posterior dislocations are easily missed: think seizures and electric shocks.
Play this puzzle#2 · Monday 26 October 2026 Easy
Source page by Photographed by User Clinical Cases 00:42, 7 November 2006 · CC BY-SA 2.5 · via Wikimedia Commons Sudden breathlessness
A tall, thin 24-year-old developed sudden left-sided chest pain and breathlessness at rest.
Answer: Pneumothorax
Why: A large left-sided dark (lucent) area with no lung markings and a visible collapsed lung edge: air in the pleural space.
Pearl: Tension pneumothorax is a clinical diagnosis (hypotension, distress, deviated trachea): decompress first, X-ray later. Small primary pneumothoraces in well patients can often be watched.
Play this puzzle#1 · Sunday 25 October 2026 Genius
Source page by CDC / Dr Thomas Hooten · Public domain · via CDC Public Health Image Library Easy to miss
A 58-year-old smoker has had a fever, rigors and a cough with rusty sputum for four days. Crackles are hard to hear.
Answer: Right upper lobe pneumonia
Why: Subtle hazy airspace opacity in the right upper zone, with preserved lung volume and no mass: right upper lobe consolidation.
Pearl: Collapse loses volume (the fissure and trachea pull up); pneumonia usually doesn't. In smokers and older adults, repeat the chest X-ray about 6 weeks after treatment to make sure an underlying tumour isn't hiding behind the consolidation.
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