The least important PE signs are those that are no longer employed because of the availability of easily performed ancillary tests . For example, the availability of accurate laboratory measures of thyroid function has reduced the importance of the ocular signs of hyperthyroidism beyond lid lag. Handheld spirometry provides an easier and more precise assessment of obstructive airway disease than Hoover’s sign and pulsus paradoxus, and pulse oxymetry may detect reduced blood oxygenation at earlier stages than cyanosis. Hence, the calls to incorporate pulse oxymetry and spirometry into the PE, and add handheld oxymeters and spirometers to the stethoscope, sphygmomanometer, and reflex hammer that a doctor already uses during patient examination [24].

Important PE findings are those in-between the previous two categories. I suggest that tutors should focus first, on missed or misinterpreted PE findings that have been shown to lead to diagnostic errors in outpatients [8] and inpatients[7], and second, on the most commonly observed PE errors by interns and residents [6]

Common diagnostic errors in primary care that had been traced back to the PE were hypertension, knee and ankle effusions, hepatomegaly, and cellulitis [8]. Suppurative thrombophlebitis, toe gangrene, dialysis catheter tunnel infection, and erysipelas were among the undiagnosed disorders because of a missed PE finding in inpatients [7]. Therefore, students should be repeatedly reminded that inspection of the skin is a part of the PE, and that a finding of rash in the context of fever is an essential PE finding that may suggest bacterial meningitis.

The highest observed error rates by interns and residents have been reported in the examination of the cardiovascular system (19 %) and respiratory system (3 %) [6]. The most common errors in the PE of the cardiovascular system were auscultation of neck vessels, palpation of the PMI, auscultation in various positions, and following radiation of murmurs [25]. Among internal medicine residents, detection rates of audio taped cardiac murmurs never exceeded 30 % [20]. It seems that the ability to diagnose mitral regurgitation, aortic stenosis, mitral stenosis, and patent ductus arteriosus by auscultation alone is not a realistic goal of undergraduate medical training. Therefore, I suggest that students should be required to detect cardiovascular PE findings that may indicate life-threatening conditions, such cannon jugular waves in the context of tachycardia, S3 gallop, or aortic insufficiency; they should be also expected to discern between normal and abnormal findings on auscultation of the heart (e.g., a cardiac murmur) that may indicate a need for further testing (e.g., echocardiography); they should be able to describe and explain the characteristics of the various murmurs and abnormal heart sounds; however, the ability to diagnose specific non-emergent abnormalities (e.g., Austin Flint murmur) on auscultation of real patients, mannequins or audiotapes should be considered optional.

The most common errors in the PE of the respiratory system were those leading to missed diagnoses of pneumonia and pleural effusion [8]. I believe that students should know that the prevalence (pretest probability) of pneumonia has been reported to be 3–7 % among outpatients with acute onset of cough [26] and 11 [27] and 12 % [28] among emergency room patients with fever or respiratory symptoms. Students should be able to detect physical signs with likelihood ratios positive for pneumonia of 3.5 or more, such as asymetric expansion of the chest and increased vocal fremitus [29], dullness on percussion and pleural friction rub [30], and heart rate above 120 [31]. Similarly, students should be able to detect physical signs with high likelihood ratios positive for pleural effusion, such as diminished vocal fremitus, dullness on percussion, diminished breath sounds, pleural friction rub, and diminished vocal resonance [32].

Other errors in the PE of the respiratory system that I have frequently encountered were locating the position of the diaphragm, percussing the cardiac dullness, and palpating the expansion of the chest. Students needed to be reminded of the anatomical landmarks of Lewis angle (second intercostal space), and the tip of the scapula (seventh intercostal space); they also needed to be shown that, during expiration, the location of the diaphragm is on the sixth, eighth, and tenth intercostal spaces on the front, side, and back, respectively; that emphysema can be diagnosed by the absence of cardiac dullness on percussion ; and that restricting the examination of the lungs to the back leaves the upper lobe unexamined.

Many students also had difficulty in mastering the technique of percussion and understanding the pathological variations of breath sounds. Specific errors in percussion included use of excessive force in delivering the blow by the plexor finger on a too-loosely placed pleximeter finger, delivery of the blow through motion at the elbow rather than at the wrist, on the middle rather than on the terminal phalanx of the pleximeter finger, and failure to promptly move away after percussion.

To correct these errors, tutors may wish to use a non-live simulation, consisting of a tabletop (simulating the chest wall) and a foam sponge (simulating the overlaying skin and subcutaneous tissue). Students are asked first to percuss the table directly by tapping on it without using a pleximeter and note the clear sound produced by its solid texture. Then they are asked to percuss, again directly, a foam sponge placed on the table and note the muffling of the elicited sound. And lastly, the tutor would demonstrate how this muffling can be avoided by indirect percussion of the sponge after exerting adequate pressure on it with the pleximeter finger. Students are asked to compare the sound elicited after various degrees of pressure on the sponge with that elicited by direct percussion of the bare tabletop. Once they grasp the importance of applying appropriate pressure with the pleximeter, they rapidly acquire the technique of delivering the blow with a wrist rather than elbow motion, of tapping rather than pressing the plexor, and of percussing at the site of the pleximeter finger (the terminal phalanx) which exerts the maximal pressure.