Coca-cola bottle sign - refers to the appearance of the orbital rectus muscles in thyroid eye disease most commonly caused by Grave’s disease. The belly of the muscle enlarges with sparing of the tendinous insertion simulating the appearance of a traditional coke bottle. This pattern of enlargement is important as in orbital pseudotumour the tendinous insertions are not spared (they are enlarged) which helps in distinguishing between the two conditions.
Paget’s disease of bone - a chronic bone disorder characterised by excessive abnormal bone remodelling. There are three disease phases; the ‘lytic’ phase predominated by osteoclastic activity, the ‘mixed phase’ with osteoblastic as well as osteoclastic activity, and the ‘sclerotic phase’ or late phase.
Case A - shows typical late phase Paget’s of the proximal femur with cortical thickening and coarsened trabeculations. This patient also has advanced hip joint osteoarthritis with flattening of the femoral head secondary to bone softening.
Case B - shows osteosarcoma arising as a complication of pre-existing Paget’s disease, which can occur in as many as 1% of cases. Note the dense osteoid matrix and the ‘hair-on-end’ type of aggressive periosteal reaction.
Elbow joint effusion - recognising an elbow joint effusion on a lateral radiograph is an essential clinical skill. The key is to detect abnormal displacement of the fat pads around the distal humerus and in particular the sail sign. In adults a radial head fracture is the most common cause of an effusion, while in children a supracondylar fracture is most common. This short video tutorial is courtesy of the RadiologyChannel.
- S - slipped = type I
- A - above = type II
- L - lower = type III
- T - through or transverse or together = type IV
- R - ruined or rammed = type V
Scotty dog sign - refers to the normal appearance of the lumbar spine posterior elements when seen on oblique views:
- the transverse process being the nose
- the pedicle forming the eye
- the inferior articular facet being the front leg
- the superior articular facet representing the ear
- the pars interarticularis (the lamina between the facets) equivalent to the neck.
If a spondylolysis is present, the pars interarticularis will have a defect and look like the Scotty dog has a collar - or doggy decapitation for those with a bloodier imagination!