Page 29 - 16_Atti_SNO_2022_flip

Proceedings SNO “LXI Congresso Nazionale SNO”
VENERDÌ, 11 NOVEMBRE

Communication LECTURE:
“HISTORIC MEMORIAL”

The anatomical illustration
of the arachnoid membrane

S. SPINNATO

Neurosurgery, Milan

“... no one can be entitled to surgery, when they can- reviewed in regard to etymology, historical aspects
not document that they have learned the art of dis- with special emphasis on the anatomical illustration.
section...” Federico II (1194-1251)

ETYMOLOGY
INTRODUCTION
The meninges are designated as “mater”: “mother”, on
The spinal cord and the brain are covered with three account of their protective role. Eristratus (ca. 310-250
layers of protective membrane called meninges. The B.C.) in the third century coined the term “meninges”
-
three meninges are named dura mater, the tough out- and “meninx”, meaning membrane in Greek. Claudius
er coat; the pia mater, the delicate inner covering; and Galen described two layers that he termed “pacheia”
-
the arachnoid, the membrane between them. The and “lepte”. He had named the outer membrane (the
-
arachnoid membrane is a delicate translucent layer dura) the “meninx sklera pacheia” (the hard, thick,
that lies in direct contact with the dura and it is sepa- membrane), and the inner (the pia), the “meninx lepte”
rated from the pia mater by the cerebrospinal fluid- (the thin membrane). These were later observed and
filled subarachnoid space, which is traversed by fine translated into Arabic by an anonymous Muslim
filaments that connect both layers, named “arach- physician as “umm al-dimagh” (mother of the brain),
noid trabeculae”. The trabecular arachnoid mem- which was later subdivided into “umm al-ghalida”
branes cross the subarachnoid space and separate this (hard mother) and “umm al-raqiqah” (thin mother). In
th
space into anatomically distinct compartments called the 11 and 12 centuries, monks of the Roman church
th
cisterns. The trabecular arachnoid membranes sup- began translating some of the Arabic versions of the
port, bind, encase, or attach to the arteries, the veins Greek writers into Latin. These terms were then trans-
and the nerves passing through the cisterns. The lated into Latin by the monk Stephen of Antioch who
arachnoid membrane is named like this due to its produced a Latin translation of Galen from the Arabic
web-like appearance. Its thinness and delicacy ac- version. Stephen of Antioch translated these two terms
count for its ignorance by the ancient anatomists, as into the Latin “dura mater” and “pia mater”.
stated by Raphael Bienvenu Sabatier (1732-1811) In the Middle Age, the dura mater was referred to as
who wrote: “The arachnoid membrane is so thin that “membrana dura”, “membrana crassa” or “mem-
it could escape notice if we were not told of its exis- brana fibrosa” (thick and tough), hence designated as
tence”. The literature on arachnoid membrane was “pachymeninx”, and it was separated from a “mem-

Corrispondenza: Dr. Salvatore Spinnato, Redazione new Magazine edizioni, via dei Mille 69, 38100 Trento (TN), e-mail: spinnato.
salvatore@virgilio.it
LXI Congresso Nazionale SNO, 9-12 novembre 2022, Riva del Garda (Trento).
Atti a cura di Bruno Zanotti e Antonio Nicolato (con la collaborazione di Ebba Buffone, Bedetto Pietralia, Giampietro Pinna)
Copyright © 2022 by new Magazine edizioni s.r.l., Trento, Italia. www.newmagazine.it ISBN: 978-88-8041-137-6

- 27 -