E2180. When “Normal” Isn’t Exactly Normal: Upper Extremity Anatomic Variants
  1. Min Kong; Mayo Clinic
  2. Andrew Sill; Mayo Clinic
  3. Jonathan Flug; Mayo Clinic
  4. Jeremiah Long; Mayo Clinic
Recognition of variant anatomy and differentiating it from pathological findings is important for radiologists to avoid potential misdiagnoses. Variant anatomy may also be the cause of a patient’s presenting symptoms. While some forms of variant anatomy are easily visualized on radiographs, others are only seen with more advanced imaging modalities such as MRI or CT. The purpose of this educational exhibit is to explore findings of common and uncommon anatomic variants of the upper extremity encountered with various imaging modalities. This presentation is aimed for not only the practicing radiologists but also the trainees in their various levels of training. We will provide practical tips to help them differentiate the asymptomatic or symptomatic anatomic variants from the pathologic findings and help them make confident and accurate diagnosis.

Educational Goals / Teaching Points
Define terminology of the variant anatomy of the upper extremities. Distinguish normal variant anatomy from pathologic findings to avoid misdiagnosis. Explore possible complications associated with variant anatomy. Explore the embryological origin of some variant anatomy examples to facilitate understanding. Synthesize the understanding of the normal variant anatomy in a quiz format. Summarize the covered materials in short sentences and reinforce audience’s understanding.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
This educational exhibit will focus on variant anatomy of the upper extremities utilizing illustrative cases. Each case will be presented in an interactive quiz format. The audience will be provided with representative imaging and a short clinical description of an anatomic variant along with potential answer choices. Each case will be followed by an answer and explanation of the findings, clinical implications, and when relevant, embryologic significance. The cases will include: humeral head pseudocyst, glenoid dysplasia, os acromiale, pseudodefect of the capitelum, supracondylar process, radial tuberosity pseudocyst, carpal bone coalition, and median nerve bifurcation.

Recognition of variant anatomy by radiologists is important and can potentially impact patient care. After viewing this educational exhibit, the audience will feel confident identifying and understanding anatomic variants of the upper extremities.