Louisville Medicine Volume 68, Issue 8 - Page 18

AUTHOR Vasudeva G . Iyer , MD
FEATURE

“ SOCIAL DISTANCING BY THE PINKY ”: AN OMINOUS CLINICAL SIGN

AUTHOR Vasudeva G . Iyer , MD

William Osler ’ s advice “ Listen to

your patient ; he is telling you the diagnosis ” has become even more relevant in this era of telehealth medicine . Apart from providing highly useful clues to the diagnosis , the manner in which a patient presents the story can also be quite entertaining . In this depressing time of the pandemic , humorous dialogues with anyone , including the patient , can light up the day . Over the years , I have come to enjoy such humor from patients more and more and appreciate the insights it provides about their personality and the underlying disorder . I am tempted to share with you one such recent instance , as it led to reverberations in my memory networks bringing up interesting medical tidbits .
A 40-year-old described his symptoms as follows : “ Doc , three months after the virus came to my town , I noticed that my left pinky started staying away from the ring finger , a little at the beginning , but increasing steadily . Now it stays far away , as if it is actually following the CDC recommendation for social distancing .” Both the patient and I laughed at this timely joke . On a more serious note , he described how it has hindered picking up stuff from his pant pocket and how more than once , the edge of the pocket almost cut through the skin between the small and ring finger . His friend , a physical therapist , advised him to use a rubber band to keep the small finger close to the ring finger . This did not work long , as the ring finger started “ social distancing ” from the middle finger . He saw his family doctor and was referred to an orthopedic specialist , suspecting dislocation of the metacarpal phalangeal joint . The X-rays of the hand did not show any abnormalities and an electromyogram ( EMG ) was requested , providing me the opportunity to be part of his medical care .
The inability to adduct the small finger , leading to the “ deviating pinky ,” results from weakness of the palmar interosseus muscle , innervated by the deep branch of the ulnar nerve ( you may recall the mnemonics PAD and DAB : palmar interossei adduct and dorsal interossei abduct ). In addition to a position of abduction , the unbalanced action of the extensor digiti minimi , tends to pull the finger up at the metacarpophalangeal ( MP ) joint as the ulnar-innervated fourth lumbrical also tends to be weak ; remember that the lumbrical muscle flexes the MP joint .
The credit for describing the peculiar posture of the small finger in ulnar neuropathy ( Figure 1 ) goes to Dr . Robert Wartenberg ( 1887- 1956 ), whose name is associated with several aspects of neurological evaluation and diagnostic signs . He wrote : “ From the physiological
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