Simplifying the upper limb peripheral motor screen: Proposing the "K" sign

The well-recognized erosion of pathoanatomic correlations in basic medical training, combined with the increasing everyday pressures of time-efficacy in patient examination, continue to place strain on junior clinicians. Over the years, many refinements to tried-and-true basic physical examination techniques have been described, allowing improvement in diagnostic yield. A multitude of "screening" techniques are available for physical assessment; however, such approaches are often nonstandardized and inconsistently taught and applied in the clinical realm. Great interexaminer inconsistency in the documentation of many forms of screening techniques also substantively undermines their respective clinical value. The current work presents a novel refinement/combination of previously described examination approaches for the assessment of peripheral upper limb (UL) motor function--the "K" sign. Having been successfully applied in both the acute and ambulatory clinical settings for several years, we feel that the technique has a useful role as a rapid and specific screening technique that is easily taught, learnt, and applied. Arguably, its employment serves to improve time efficacy in the screening examination, and may even improve diagnostic yield through its reliable reproducibility and provision of direct bilateral comparison. Its inherent simplicity also lends itself well to high levels of uptake (and retention) by medical students and junior clinicians alike. On top of presenting the simple screening test itself, we offer a simple means of subsequent notation for the patient's case note record, again in the hope of standardization and endurance of clinical value beyond the time of patient examination.