Mendel-Bechterew Reflex

MENDEL-BECHTEREW REFLEX (Mendel) consists of the plantar flexion of the toes upon percussion of the dorsum of the foot in the region of the cuboid or lateral tarsal bones (see figure); normally, this is usually accompanied by dorsiflexion of the toes. This reflex indicates the presence of pyramidal tract lesions; in terms of frequency in such cases, it is significantly inferior to Babinski's sign and appears much later than it in acute cases. In pyramidal tract lesions, plantar flexion of the toes often accompanies other components of the extensor synergy of the lower extremities, and it can also be elicited in isolation or associated with other components of the extensor synergy when percussing other areas (from the calcaneus—Bechterew's calcaneal phenomenon, from the plantar surface of the metatarsal region—Zhukovsky's sign, from the inner surface of the leg, the region of the tibialis anterior muscle, the internal condyle, and some authors describe it from even higher areas as well). The Mendel-Bechterew reflex can therefore be considered, along with other symptoms described above, as a component of extensor synergy (Filimonov). Appearing in the residual phase of a complete transverse spinal cord lesion, the Mendel-Bechterew reflex is also present and well expressed in cases of systemic pyramidal tract lesions (e.g., amyotrophic lateral sclerosis, Erb's type spinal paralysis), in which Babinski's and Oppenheim's signs are poorly expressed. In complete transverse lesions of the spinal cord, the Mendel-Bechterew reflex has a slow tonic character. In cases where defense reflexes are sharply expressed, it may be displaced by the latter, and percussion of the dorsum of the foot may cause, instead of plantar flexion of the toes, a shortening reflex of the lower extremities with tonic extension of the toes, especially the big toe. The Mendel-Bechterew reflex is often observed together with extensor contractures and increased reflex excitability.

N. Propper. MENZBIER, Mikhail Alexandrovich (1855–1935), member of the Academy of Sciences of the USSR, professor at Moscow University, doctor of zoology. Upon graduating from Moscow University, he became a privat-docent in zoology, and later a professor of comparative anatomy. He lectured at Moscow University on zoogeography and game birds. His specialty was zoogeography and ornithology. Menzbier is the founder of modern zoogeography of the Palaearctic region. Among his major scientific works, mention should be made of "Ornithological Geography of European Russia," which is a fundamental treatise on zoogeography in general (Scientific Memoirs of Moscow University, 1882). In his work on the ornithology of Turkestan (1886–1890), Menzbier gives precise systematic descriptions of the diurnal and nocturnal birds of prey of Turkestan. "Birds of Russia" (Moscow, 1895; latest ed., Moscow, 1918) marked an epoch in the study of the birds of our country. Among Menzbier's general biological works, one must note "Forms of Social Order in Animals" (Petrograd, 1922) and "The Place Occupied by Man in the Animal System" (a chapter in the book by D. Zernov, Textbook of Descriptive Human Anatomy, part 1, Moscow, 1924). Among his textbooks for higher education institutions, one should name "Introduction to the Study of Zoology and Comparative Anatomy" (Moscow, 1906; 4th ed., Moscow, 1924) and "Zoogeographical Atlas" (Moscow, 1912; explanatory text published in 1917–1918). Menzbier did a great deal to propagate Darwin's ideas ("For Darwin," Moscow-Leningrad, 1927); under Menzbier's editorship and with the inclusion of a number of his articles, the four-volume "Complete Works of Charles Darwin" was published (Moscow-Leningrad, starting from 1925). Menzbier is the author of a number of essays that serve as high examples of scientific popularization.