Animal and animal produce inspired signs

Animal and animal produce inspired signs may sound a little silly, but the radiology literature is replete with such signs, some more fanciful than others.

Fish and marine life

• cluster of black pearls sign

• endosteal scalloping: medullary cavity masses, e.g. multiple myeloma

• fish vertebra (also known as codfish vertebra): biconcave vertebrae as seen in osteoporosis

• fishtail deformity of the elbow: due to abnormal trochlear ossification following a distal humeral fracture in childhood 

• fishtail pancreas: rare anatomic variant of the pancreas

• lobster claw sign of papillary necrosis

• manta ray sign of bladder exstrophy

• scallop sign of rheumatoid arthritis

• shrimp sign of cerebellar progressive multifocal leukoencephalopathy

• vertebral scalloping: may be anterior or posterior border

Birds

• bird beak sign of achalasia (also known as rat tail sign)

• beak sign of arterial dissection or of sigmoid volvulus

• eggshell calcification of silicosis and occasionally sarcoidosis

• gull wing appearance of erosive osteoarthritis

• hummingbird sign or penguin sign

• owl-eyes sign of anterior spinal cord infarction etc. 

• pooping duck sign of triquetral fracture

• swallow tail sign showing normal presence of substantia nigra

• swan neck deformity of rheumatoid arthritis

• winking owl sign

Mammals

• anteater nose sign of calcaneonavicular coalition

• bat's wing

  • pulmonary opacities, e.g. in alveolar edema

  • 4^th ventricle (Joubert anomaly and related syndromes)

• bear's paw sign: xanthogranulomatous pyelonephritis

• beaver tail liver

• Brahma bull sign: femoral neck osteochondroma

• buffalo chest: bilateral pneumothoraces due to abnormal communication between the pleural spaces

• buffalo hump: accumulation of fat posterior neck and chest

• bull's eye: evoked in the mind's eye by many a pathology

• bunny waveform sign: Doppler waveform in subclavian steal syndrome

• dog ear sign: fluid/blood in pelvic peritoneal recess

• dromedary hump: anatomic variant of the renal outline

• dural tail: of meningioma and several other dural-based lesions

• ears of the lynx sign: hereditary spastic paraplegia

• elephant-on-a-flagpole sign: enlarged renal pelvis

• eye of tiger sign: classical of Hallervorden-Spatz syndrome

• feline esophagus: horizontal striations seen on barium swallows as a variant of normal

• giraffe sign

• hidebound sign of gastrointestinal scleroderma

• human

  • Jack and Jill lesion: bucket handle tears of both menisci

  • knuckle sign (PE)

  • maiden waist sign (RPF)

  • Popeye sign

  • walking man sign

• ivory phalanx sign of psoriatic arthritis

• ivory vertebra sign

• joint mouse: intra-articular loose body resulting from osteochondritis dissecans

• leather bottle stomach: of linitis plastica

• leopard skin sign or tigroid pattern

• moose head appearance of corpus callosal dysgenesis

• panda sign

  • of the midbrain in Wilson disease

  • of sarcoidosis

• piglet sign of osmotic demyelination

• pleural mouse

• raccoon eyes sign

• rat bite erosions of gout

• rat tail sign of arterial dissection or achalasia (also known as bird-beak sign)

• Scottie dog sign

• Snoopy sign

• staghorn calculus: struvite renal calculi

• tigroid pattern or leopard skin sign

• zebra sign: remote cerebellar hemorrhage

• zebra stripe sign: osteogenesis imperfecta

Arthropods

• abdominal cocoon: encapsulating peritoneal sclerosis

• butterfly fracture

• butterfly glioma: glioma crossing midline to the contralateral hemisphere

• butterfly shape of the grey matter of the spinal cord

• butterfly vertebra

• caterpillar sign: of pyloric stenosis

• spider web: intrahepatic veins in hepatic venous outflow obstruction

Reptiles

• cobra head sign of ureterocele

• snake-eye appearance: pathology of anterior horns of cervical grey matter

• snake eyes

  • appearance of the facial canal in the petrous temporal bone

  • alternative name for owl-eyes sign of spinal cord infarction

• snake sign (or serpent sign)

• turtleback sign (schistosomiasis)

Micro-organisms

• plankton sign: diagnostic on ultrasound of an exudative pleural effusion

Fictional creatures

• cyclops lesion: usually post-ACL repair

• Medusa head (caput Medusae)

  • a sign of developmental venous anomaly (DVA) 

  • a sign of severe portal hypertension

• Shmoo sign: left ventricular enlargement

Animal product foods

• cervical hamburger sign: normal cervical facet joints on axial CT

• head cheese sign of hypersensitivity pneumonitis

• honeycomb lung of UIP/pulmonary fibrosis

• ice cream cone sign of the middle ear ossicles

• ice cream cone sign of vestibular schwannoma

• mesenteric hamburger sign (also called sandwich sign): mesenteric nodal mass

• omental cake: metastases to omentum

• sausage digit: underlying inflammatory arthritis or dactylitis

• water bottle sign: massive pericardial effusion