Michele Landolfi

Michele Landolfi (1878 – 1959) medico italiano.

Landolfi studied pulmonary tuberculosis and invented the phonacoscope to aid in diagnosis.

Chief Editor of the Italian journals “Folia Medica” and “Riforma Medica” and long time Professor of Medical Semiotics at the University of Naples. Landolfi was founder and first President of the Neapolitan section of Associazione Volontari Italiani del Sangue (AVIS)

Best remembered for Landolfi sign in severe aortic regurgitation described in 1909


  • Born 3 march 1878, Airola, Italy
  • 1902 – graduated medical school in Naples as a pupil of Castellino, Bianchi and Cardarelli
  • 1903 – Assistant to Domenico Capozzi at the l’Ospedale degli Incurabili.
  • 1904 – Lecturer at III Clinica medica di Gaetano Rummo
  • 1906 – Invenented and patented the ‘fonacoscopio’ for the diagnosis of pulmonary tuberculosis
  • 1919 – Ran for local government for the “Democratico sociale”
  • Professor of Semiotica Medica nell’Uni-versità di Napoli “Federico II”
  • Honors include: Commendatore della Corona d’Italia and Cavaliere dell’Ordine Mauriziano
  • Died 7 March 1959, Napoli

Medical Eponyms

Landolfi sign (1909)

Rapidly alternating systolic constriction and diastolic dilation of the pupil occurring in severe aortic regurgitation. Believed to be an exaggeration of the physiologic circulatory hippus in the iridal vessels due to high pulse pressure and large stroke volume

Pupillary hippus is the spasmodic, cyclical and bilaterally in-phase fluctuations in pupil size in the absence of external influences such as luminance, mood and fixation. Its mechanism remains unclear but is hypothesised to be due to the continuous neurologic antagonism of the SNS and PSNS as well as respiratory and cardiac activity.

Landolfi examined twenty-four patients with grave aortic insufficiency, and found in one circulatory hippus. The patient suffered from arteriosclerosis with aortic insufficiency and hypertrophy of the left ventricle. A rapid alternate contraction and dilatation of pupil was observed. He was also able to produce this sign in three other patients after giving fifteen drops of tincture of digitalis a day for four days. He also observed the circulatory hippus in a dog with experimental aortic insufficiency after the administration of heart stimulants.

New York Medical Journal 1909
Video: Landolfi Sign: Saini et al. Am J Med. 2017

Video: Landolfi Sign: Rapid alternate constriction and dilation of the left pupil occurring synchronously with heartbeat [Saini et al. Am J Med. 2017]

Landolfi Sign: Saini et al. Am J Med. 2017

Key Medical Attributions

Phonacoscopy (fonacoscopio)

While studying pulmonary tuberculosis, Landolfi and Ranieri Papale described a new method of combined auscultation and percussion. They went on to develop the phonacoscope for the diagnosis of disease which he patented and marketed with Carlo Erba in Milan.

  • Device:  A bell-shaped resonating chamber containing a percussive hammer.
  • Technique:  The patient holds the instrument on the anterior thoracic wall and provides a uniform percussion note for the physician to detect by listening to the posterior chest.
  • Use: Eliminates the variability of a clinician’s percussion note. Useful in diagnosing pneumonia and pleurisy with effusion, pulmonary tuberculosis and other lung conditions that change the acoustic conduction of the thoracic cavity. 

Major Publications


eponymictionary CTA


the person behind the name

Emergency Medicine Trainee based in Perth, Western Australia. Keen interest in ultrasound, rural health and water-based activities.

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