Lasègue test


What is the actual eponymous medical sign/syndrome/repair/classification…

  • 1864 Lasègue 
  • 1880 Lazarević
  • 1881 J. J. Forst

the patient is placed on the bed in supine position, and we take the foot of the affected limb in one hand… holding the leg in extension, we flex the thigh on the pelvis. Raising the limb only a few centimetres produces a sharp pain at the level of the sciatic notch…We replace the limb and proceed to another manoeuvre which is only a confirmatory test. If we now flex the leg on the thigh, we can flex the thigh on the pelvis without producing any painful sensation”.

Forst stressed the precautions of flexing the thigh slowly and sliding the heel on the bed and securing cooperation to relax the limb completely. “What is happening?”, he asked.

…the sensation of pulling is very probably due to compression of the sciatic nerve by muscular contraction. On the other hand, if we flex the leg on the thigh, we paralyse the extensors of the thigh on the pelvis… there is greater ease in raising the limb with less compression of the sciatic nerve … We consider this sign to be pathognomonic of sciatica, for we have not found it in any other affection of that region

Associated Persons
Alternative names
  • Lasègue test
  • Lasègue’s sign
  • Lazarević sign
  • Lazarićev znak
  • Straight leg raise (SLR)
  • Lasègue C. Considérations sur la sciatique. Archives générales de médecine 1864;6(II):558–580
  • Lazarević LK. Ischias postica contunnii – jedan prilog za njenu diferencijalnu dijagnozu. Srpski arhiv za celokupno lekarstvo. 1880;7: 23-35
  • Forst JJ. Contribution á l’étude clinique de la sciatique. Thèse No 33. Facultè de Mèdecine, Paris 1881
  • Lazarević LK. Ischias postica Cotunnii. Ein Beitrag zu deren Differential-Diagnose. Allgemeine Wiener medizinische Zeitung, 1884; 29: 425-426

eponymictionary CTA


the names behind the name

BA MA (Oxon) MBChB (Edin) FACEM FFSEM. Emergency physician, Sir Charles Gairdner Hospital.  Passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

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