Case 12 - Triquetral Fracture

Triquetral fractures are the second most common carpal bone fracture, often occurring along the dorsal aspect of the carpal bones. While there are multiple mechanisms for the method of injury, the most common method is impaction from the ulnar styloid, which acts as a chisel, along the dorsal cortex of the triquetrum.  Dorsal avulsion injuries are best visualized on the lateral radiograph, as seen in this case, as a result of the strong dorsal ligaments avulsing off the dorsal cortex.

Case courtesy of Dr. Matt Skalski

One of my favorite signs in all of radiology is the "Pooping Duck Sign," which is present on the lateral radiograph. The duck is the composed of the superimposition of the Scaphoid and the Lunate bones, while the 'poop' is the avulsed bony fragment of the triquetrum.

Here is a normal lateral radiograph of the wrist with the Pooping Duck sign below.

Courtesy of Dr. Michael L. Richardson, M.D.

Courtesy of Dr. Michael L. Richardson, M.D.

Image Courtesy of Radiology Tips (http://radiologytips.com/modality/radiography/pooping-duck/)

Nearly all of these fractures are treated non operatively; rarely is any surgery required.  As an aside, the skeletal anatomy website by Dr. Richardson is extremely helpful and one I recommend to add to your armamentarium as a quick resource for bony anatomy you might need throughout training.


References:

Case courtesy of Dr Matt Skalski, https://radiopaedia.org/.  From the case: https://radiopaedia.org/cases/57109

Radiographic Skeletal Anatomy by Michael L. Richardson, M.D. at the University of Washington:
http://uwmsk.org/RadAnatomy.html

Radiology Tips:
http://radiologytips.com

Case 12 - Pain

Case 11 - Trauma, MVC

In most significant trauma, both blunt and penetrating, there will often be multiple findings and you don't want to let satisfaction of search get you.  This case demonstrates a minuscule right pneumothorax, with air noted in the anterior costophrenic recess. Subpleural groudglass in the lingula is also present, representing a pulmonary contusion.  Additionally, there is a SUBTLE sternal body fracture.  This patient also had a couple of subtle, non-displaced rib fractures, but I didn't include those as some of the images on purpose.  The things I've seen folks miss the most on trauma are small pneumothoraces, non-displaced rib, sternal, and vertebral body/transverse process fractures, and small mediastinal hematomas. Be sure to always look in these regions for abnormalities. In trauma, I always look at three things on the sagittal series - the sternum, vertebral bodies, and diaphragms looking for injury. If I see a sternal fracture, I will also look at the retrosternal space searching for a hematoma, which can be very small. Reexamining the vessels is also important to assess for underlying vascular injury.  I will also run the spine on the axial and coronals looking for transverse process fractures.  I've included a link to a good radiographics article for blunt thoracic trauma.

MDCT of Blunt Thoracic Trauma (Radiographics)