Radiopaedia Blog: Radiology signs

The term licked candy stick appearance refers to tapering of the tips of the metacarpal / tarsal bones, phalanges or clavicles. This finding can be seen in advanced cases of:

Psoriatic arthritis: enthesitis and marginal erosions destroy the peripery of the bone, leaving a thinned central region. This also leads to the "pencil in cup deformity". 

Rheumatoid arthritis: marginal erosions and destruction of the joint, due to destructive pannus, also may leave a tapered portion of bone.

Leprosy: atrophy and resorption of bone due to deinvervation, begins distally in the colder regions of the body and progresses proximally. 

• Corkscrew sign - describes the spiral appearance of the distal duodenum and proximal jejunum in the setting of midgut volvulus on contrast studies. In patients with congenital malrotation of the midgut, the distal duodenum and proximal jejunum do not cross the midline and instead pass inferiorly. These loops are predisposed to twist on their shortened mesentery creating the classic corkscrew appearance of midgut volvulus.

• Hyperdense MCA sign - increased density within the middle cerebral artery on a non-contrast CT of the brain due to the presence of acute thrombus, in this case on the left. This is one of the few signs that my be identified during the first few hours (hyperacute phase) of MCA territory infarction.

• Crazy paving - a CT chest appearance where the combination of septal thickening and alveolar ground-glass opacity creates a pattern that mimics paving. The sign is classically described in pulmonary alveolar proteinosis but can be caused by many other lung pathologies.