I have a passion for interesting x-rays. All of my colleagues know that by now. I'll have just arrived in the ED for my night shift and still be shoving my backpack under the counter when I'll hear a not-so-uncommon comment, "We had a great case today." These stories always energize me. The sharing, the learning, the awesome pickup, the right fight for the patient all remind me of why we do this job.
The signing out doc (knowing my absolute favorite thing is a wrist radiograph) recently popped open some radiographs on the computer, announcing, "You are going to love this."
I scanned the AP and oblique hand films while he continued, "The patient fell last night and today came in because the hand and wrist were painful and scratched up." He pointed to the webspace between the ring and little finger, and cryptically added, "The odd thing is the patient felt like his knuckle was missing."
Finally I took a stand, "I don't like this little thing here [red arrow], and I don't like that sclerotic line there." Toggling back and forth from AP to oblique, I waffled, "I'm just not sure. It could be OK."
Grinning while taking control of the mouse, he said, "That was the orthopedist's opinion until I told him to look at the wrist films." On the external oblique, the displaced fragment of the fifth metacarpal base stood out clear as day. He got me.
Going back to the hand, I knew I had picked up some of the clues. There had to be more there. Something that I had missed or forgotten. And I had.
I had forgotten to look at the parallel M lines. One M line connects all the most proximal sclerotic lines of the carpal bones from the base of the thumb to the little finger. The other M line connects the sclerotic lines at the base of the metacarpals. These two lines are usually only 1-2 mm apart. When focused on these lines, the wide gap at the base of the fifth is glaringly obvious, and the double density increased sclerotic marking at the base of the fourth makes total sense.
I'd momentarily forgotten what normal looked like. The fifth metacarpal base always articulates completely across the top of the hamate. A quick refresher on a normal hand AP would have resolved the question of whether our patient had normal metacarpal-carpal articulation. He did not.
Fortunately, my astute friend had gotten additional views, the patient received appropriate care, and I relearned a valuable lesson.
Tips to Remember: Know normal to pick up the abnormal. Actually look at a normal film if you are unsure. Additional views can add significant perspective.