The Bekhterev–Jacobsohn reflex, or Jacobsohn's finger flexion sign, is a

clinical sign Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

found in patients with pyramidal tract lesions of the upper limb. In this condition, stroking the dorsum of the forearm, in the area of the

distal radius The radius or radial bone (: radii or radiuses) is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is longer ...

, with the arm

supine In grammar, a supine is a form of verbal noun used in some languages. The term is most often used for Latin, where it is one of the four principal parts of a verb. The word refers to a position of lying on one's back (as opposed to ' prone', l ...

causes abduction of the hand and

flexion Motion, the process of movement, is described using specific anatomical terminology, anatomical terms. Motion includes movement of Organ (anatomy), organs, joints, Limb (anatomy), limbs, and specific sections of the body. The terminology used de ...

of the fingers. It is analogous to the Bekhterev–Mendel reflex in the lower limb. The reflex is named after

Vladimir Bekhterev Vladimir Mikhailovich Bekhterev ( rus, Влади́мир Миха́йлович Бе́хтерев, p=ˈbʲextʲɪrʲɪf; 20 January 1857 – 24 December 1927) was a Russian neurologist and the father of objective psychology. He is best known fo ...

and

Louis Jacobsohn-Lask Louis Jacobsohn-Lask (born Louis Jacobsohn; 2 March 1863, in Bromberg – 17 May 1941, in Sevastopol) was a Germans, German neurologist and neuroanatomist. He studied medicine at the University of Berlin under Heinrich Wilhelm Waldeyer, Rudolf V ...

References

Medical signs Reflexes {{med-sign-stub