SET T0030 -
Emergency Department -
Mixed Cases

Normal radiograph. No fracture. Normal carpo-metacarpal joint (CMJ) alignment.

Comments:

• You might have been concerned that there is subluxation at the 1st CMJ.
• Be very wary of overcalling a subluxation at this extremely mobile joint. The thumb CMJ is a very lax joint with a wide range of normal alignments.
• Fortunately, traumatic CMJ subluxation of the thumb is infrequent.
• A metacarpal fracture, or a Bennett's fracture-dislocation, are much more common injuries.

The outstanding medical artist, Philip Wilson, has created really useful and helpful anatomical artworks relating to the 1st CMJ. His drawings illustrate the various movements and extraordinary degree of mobility that occur normally at this joint . . .

See : Accident & Emergency Radiology : A Survival Guide (3rd edition) : Pages 154-155

Normal radiograph. No adverse finding. Specifically, the hip joints are anatomically within normal limits.

Both hips are abnormal - bilateral slipped upper femoral epiphyses.

Abnormal Kline's line (red lines).

Abnormal Capener's sign (green arrows); sometimes this sign is referred to as the "metaphyseal extrusion sign".

NB See the previous case, in this set, which shows the normal appearances.

Comment: most commonly this abnormality occurs on one side only, and that allows the reader to compare the symptomatic side with the (presumed) normal and asymptomatic side. In this patient, it is likely that the slip occurred on one side initially and then following a few weeks of putting more weight through the unaffected hip the second slip occurred.

The various radiological lines, signs, and findings are described clearly and excellently in:

http://orthopaedicprinciples.com/2010/12/slipped-capital-femoral-epiphysisscfe/

Blow-out fracture of the left orbit.

The black eyebrow sign (red arrow) is the diagnostic feature. The other possible radiographic findings with this fracture are absent - or very, very, subtle - in this patient.

Note that the CT coronal section shows the fracture of the orbital floor and the peri-orbital free air. The air has passed into the orbit from the maxillary antrum, via the fracture, and resulted in the "Black Eyebrow" seen on the plain (occipito-mental) radiograph.