Lunate and Perilunate dislocation


    Lunate and Perilunate dislocation

    A 36F presenting with wrist pain after a fall on an outstretched hand. She has pain and swelling over the dorsal-radial aspect of her hand. Her xray is below, what is the diagnosis?


    It’s the spilled tea cup sign, but can you remember which dislocation it stands for?? It is the lunate dislocation.

    Both the perilunate and the lunate dislocations occur because of forceful dorsiflexion and impact on an outstretched hand, usually in the setting of a fall or from a MVC. This force produces a pattern of injury with progressive instability. The first stage, and least severe, is a scapholunate dissociation (Terry Thomas sign). With more force, more ligaments are torn away from the carpal bones and a perilunate dislocation results.  And with even more force still, the dorsal radiocarpal ligament is torn and the lunate is dislocated volarly.


    Both dislocations are best view on lateral wrist radiographs. Perilunate dislocations will show the capitate not sitting in the cup of the lunate, but dorsally displaced. Furthermore, a line through the radius and lunate with not intersect the capitate


    A lunate dislocation will show the spilled teacup sign with the lunate displaced volarly. The lunate will not articulate with the capitate or radius.

    Both injuries will require emergent reduction and likely surgical repair. Complications include arthritis, median nerve dysfunction and decreased ROM.


    Escarza R, Loeffell MF, Uehara D. “Wrist Injuries.” Chapter 266. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide 7e. Eds. Judith E. Tintinalli, et al. New York, NY: McGraw-Hill, 2011

    • Welcome! This is the website for the Mount Sinai Emergency Ultrasound Division. It serves as an information resource for residents, fellows, medical students and others seeking information about point-of-care ultrasound. There is a lot ofRead more

    • renal handling of water

      If you were on a tea & toast diet, how much water would you need to drink before you develop hyponatremia? I haven’t seen anyone work out the numbers before so here are my calculations. AndRead more

    • acute acidemia physiology

      As alluded to in the first post, don’t be fooled by a “normal” potassium in the setting of DKA because osmotic diuresis and H+/K+ exchange means that total body potassium is actually LOW. You all knowRead more

    • renal handling of potassium

      the first symptom of hyperkalemia is death Earlier post covered temporizing measures to counter hyperkalemia — namely, intracellular shift, increasing cardiac myocyte threshold potential. Give furosemide if the patient still urinates and consider dialysis, but then askRead more

    • bicarbonate revisited

      Previous post reviewed the safety of balanced crystalloids in hyper K. But what was up with serum bicarbonate decreasing with saline administration? This post introduces a new way of looking at the anion gap to possiblyRead more

    • hyperkalemia and balanced crystalloids

      Is it safe to give LR or plasmalyte to a hyperkalemic patient (these balanced crystalloids have 4-5 mEq/L K as opposed to 0 mEq/L K in normal saline)? Postponing the discussion of renal handling of potassium toRead more

    • hyperkalemia physiology

      You’ll likely encounter hyperkalemia on your next Resus / Cardiac shift, and you’ll instinctively treat it. But take a moment to review the fascinating physiology behind the “cocktail”! First, consider how K+ is buffered byRead more

    • Slow down your tachycardia (but not really)

      You’re sitting in resus bemoaning the departure of your most beloved attending when suddenly a patient wheels in without warning. The patient looks relatively stable but the triage RN tells you her heart rate wasRead more

    • Otitis externa: use the ear wick!

      Acute otitis externa (AOE) is a common complaint seen in pediatric as well as adult emergency departments. AOE is typically not accompanied by acute otitis media, although concurrent cases are possible. Also called “swimmer’s ear”Read more