Humphrey Ridley (1653–1708): 17th Century Evolution in Neuroanatomy and Selective Cerebrovascular Injections for Cadaver Dissection

Jai Deep Thakur, M.D.; Ashish Sonig, M.D., M.S., M.Ch.; Prashant Chittiboina, M.D., M.P.H.; Imad Saeed Khan, M.D.; Rishi Wadhwa, M.D.; Anil Nanda, M.D., M.P.H.


Neurosurg Focus. 2012;33(2):e3 

In This Article

Abstract and Introduction


Humphrey Ridley, M.D. (1653–1708), is a relatively unknown historical figure, belonging to the postmedieval era of neuroanatomical discovery. He was born in the market town of Mansfield, 14 miles from the county of Nottinghamshire, England. After studying at Merton College, Oxford, he pursued medicine at Leiden University in the Netherlands. In 1688, he was incorporated as an M.D. at Cambridge. Ridley authored the first original treatise in English language on neuroanatomy, The Anatomy of the Brain Containing its Mechanisms and Physiology: Together with Some New Discoveries and Corrections of Ancient and Modern Authors upon that Subject.


Ridley described the venous anatomy of the eponymous circular sinus in connection with the parasellar compartment. His methods were novel, unique, and effective. To appreciate the venous anatomy, he preferred to perform his anatomical dissections on recently executed criminals who had been hanged. These cadavers had considerable venous engorgement, which made the skull base venous anatomy clearer. To enhance the appearance of the cerebral vasculature further, he used tinged wax and quicksilver in the injections. He set up experimental models to answer questions definitively, in proving that the arachnoid mater is a separate meningeal layer. The first description of the subarachnoid cisterns, blood-brain barrier, and the fifth cranial nerve ganglion with its branches are also attributed to Ridley.

This historical vignette revisits Ridley's life and academic work that influenced neuroscience and neurosurgical understanding in its infancy. It is unfortunate that most of his novel contributions have gone unnoticed and uncited. The authors hope that this article will inform the neurosurgical community of Ridley's contributions to the field of neurosurgery.

In the modern microneurosurgical era, cadaveric dissection holds an important position for aspiring and practicing neurosurgeons, not only to improve the understanding of the surgical anatomy but also as a tool of advancing neurosurgical operative techniques. Professors Yaşargil[15] led the evolution in the understanding of the surgical neuroanatomy in the late 20th century. Although the use of selective colored cerebrovascular injections in cadaver dissections has recently become a routine practice to enhance the cerebral vasculature, it is an old art that was introduced more than 300 years ago.[1,8,13,14,16,18]

Humphrey Ridley, M.D. (1653–1708), a British physician in the 17th century, injected mercury and tinged wax into the cerebral veins of freshly executed criminals, taking advantage of the considerable venous engorgement to demonstrate the anatomy of the venous plexus of the skull base. His work is reflected in the naming of the circular sinus the "Ridley sinus." Despite this, Ridley remains a relatively unknown figure of the postmedieval era of neuroanatomical discovery.[4,9,11,16]

We reviewed the published works on neuroanatomy authored by Ridley to understand his novel contributions to skull base anatomy and to understand the innovative cadaveric dissections and research methods that he used. This historical vignette attempts to describe Ridley's academic work and his influence on neuroscience and neurosurgical understanding.