Insights into neurologic localization by Rhazes, a medieval Islamic physician.
Rhazes was born at Ray near modern Teheran in 864 AD. He wrote over 200 scientific treatises, many of which had a major impact on European medicine. His best known manuscript is Liber Continens, a medical encyclopedia. Herein are described Rhazes's contributions to neurology, focusing on his description of cranial and spinal cord nerves and his clinical case reports, which illustrate his use of neuroanatomy to localize lesions. Relevant passages from facsimiles of the manuscripts Kitab al-Hawi (Liber Continens) and Al-Mansuri Fi At-Tibb (Liber Al Mansoori) were translated, reviewed, and used as references. In addition, Medline, Web, and manuscript searches on Rhazes and the history of medieval and Islamic medicine and neurology were conducted. Rhazes stated that nerves had motor or sensory functions, describing 7 cranial and 31 spinal cord nerves. He assigned a numerical order to the cranial nerves from the optic to the hypoglossal nerves. He classified the spinal nerves into 8 cervical, 12 thoracic, 5 lumbar, 3 sacral, and 3 coccygeal nerves. Rhazes showed an outstanding clinical ability to localize lesions, prognosticate, and describe therapeutic options and reported clinical observations, emphasizing the link between the anatomic location of a lesion and the clinical signs. Rhazes was a pioneer in applied neuroanatomy. He combined a knowledge of cranial and spinal cord nerve anatomy with an insightful use of clinical information to localize lesions in the nervous system.