- A dictionary of medical eponyms

Lasègue's sign

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A sign frequently seen in lumbar root or sciatic nerve irritation: when patient is supine with hip flexed, dorsiflexion of ankle causes pain or muscle spasm in the posterior thigh.

Pierre Astruc relates a story of Lasègue's discovery of the sign: On one Sunday morning he thinks of the question which he had been asked by Inspector General Dujardin-Baumetz* how to discover the malingerer simulating sciatica. He promised to study the question: it is ever present in his thoughts. While smoking his pipe, he sees Mme. Lasègue seated at the piano while his son-in-law, Cesbron, is tuning his violin. Is not the string stretched over the bridge like the sciatic nerve which is made taut on the ischium when the lower extremity is elevated? Undoubtedly as he listens to the classical music he has formulated the answer to the Inspector General's question. Tomorrow he will look for the sign in his clinic . . .

The sign did not, however, appear in his Considération sur la sciatique. Detective work by Robert Wartenberg (1887-1956) revealed that it was only years later that his pupil J. J. Forst put the sign on record.

The Serbian neurologist Laza K. Lazarevič (1851-1891) first published a description in 1880 in the Sebian Archives, independently of Forst. He then described the sign fully and accurately in 1884.

*Georges Saintfort-Octave Dujardin-Beaumetz (1833-1895).

We thank Srdjan Milovanovic and Michael Webb for information submitted.


  • Laza K. Lazarevič:
    Ischias postica Cotunnii: a contribution to the differential diagnosis.
    Srpski arhiv za celokupno lekarstvo [Serbian Archives of Medicine], Beograd, 1880, 7: 23-35.
  • J. J. Forst:
    Contribution à l’ètude clinique de la sciatique. Paris. Thèse No. 33, 1881.
  • Laza K. Lazarevič:
    Ischias postica Cotunnii. Ein Beitrag zu deren Differential-Diagnose.
    Allgemeine Wiener medizinische Zeitung, 1884, 29: 425-426 et seq.
  • D. T. Dimitrijevic:
    Lasegue sign. Neurology, September/October 1952, 2 (5): 453-454.
  • D. T. Dimitrijevic:
    [Problem of Lasegue's sign.] Srpski archiv za celokupno lekarstvo, Novemeber 1952, 80 (11): 1068-1072., Novemeber 1952, 80 (11): 1068-1072.
  • M. Pecina, P. Keros:
    [The Lazarevic-Lasegue sign] [Article in Croatian]
    Lijec Vjesnik, Zagreb, 1970, 92 (2): 228-231.

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