Calcar avis
Encyclopedia
On the medial wall of the posterior cornu
of the lateral ventricle is a longitudinal eminence, the calcar avis, which is an involution of the ventricular wall produced by the calcarine fissure
. For much of the 19th century this ridge was known as the hippocampus minor'
It is sometimes visible on ultrasonogram. It can simulate a clot.
. A classical allusion was introduced later with the term pes hippocampi, which may date back to Diemerbroeck in 1672, introducing a comparison with the shape of the folded back forelimbs and webbed feet of the Classical hippocamp
us (Greek: ἱππόκαμπος), a sea monster with a horse's forequarters and a fish's tail. At a subsequent stage the hippocampus was described as pes hippocampi major, with the calcar avis being named pes hippocampi minor.
The renaming of the hippocampus as hippocampus major, and the calcar avis as hippocampus minor, has been attributed to Félix Vicq-d'Azyr
systematising nomenclature of parts of the brain in 1786. While "hippocampus minor" was used interchangeably with "calcar avis" for much of the 19th century, for a few years after 1861 the former name was subjected to publicity and ridicule when the hippocampus minor became the centre of a dispute over human evolution
between Thomas Henry Huxley and Richard Owen
, satirised as the Great Hippocampus Question
. The term hippocampus minor fell from use in anatomy textbooks, and was officially removed in the Nomina Anatomica
of 1895, but still featured in the Encyclopædia Britannica
of 1926, and appeared in general dictionaries as late as 1957.
Posterior horn of lateral ventricle
The posterior horn of the lateral ventricle passes into the occipital lobe, its direction being backward and lateralward, and then medialward....
of the lateral ventricle is a longitudinal eminence, the calcar avis, which is an involution of the ventricular wall produced by the calcarine fissure
Calcarine fissure
The calcarine fissure is an anatomical landmark located at the caudal end of the medial surface of the brain. Its name comes from the Latin "calcar" meaning "spur."-Anatomy:...
. For much of the 19th century this ridge was known as the hippocampus minor'
It is sometimes visible on ultrasonogram. It can simulate a clot.
Name
The ridge was originally described by anatomists as the calcar avis, while the ridge running along the floor of the temporal horn of the lateral ventricle was described by various names, in particular as the hippocampusHippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
. A classical allusion was introduced later with the term pes hippocampi, which may date back to Diemerbroeck in 1672, introducing a comparison with the shape of the folded back forelimbs and webbed feet of the Classical hippocamp
Hippocamp
The hippocamp or hippocampus , often called a sea-horse in English, is a mythological creature shared by Phoenician and Greek mythology, though the name by which it is recognised is purely Greek; it became part of Etruscan mythology...
us (Greek: ἱππόκαμπος), a sea monster with a horse's forequarters and a fish's tail. At a subsequent stage the hippocampus was described as pes hippocampi major, with the calcar avis being named pes hippocampi minor.
The renaming of the hippocampus as hippocampus major, and the calcar avis as hippocampus minor, has been attributed to Félix Vicq-d'Azyr
Félix Vicq-d'Azyr
Félix Vicq d'Azyr was a French physician and anatomist, the originator of comparative anatomy and discoverer of the theory of homology in biology.-Biography:Vicq d'Azyr was born in Valognes, Normandy, the son of a physician...
systematising nomenclature of parts of the brain in 1786. While "hippocampus minor" was used interchangeably with "calcar avis" for much of the 19th century, for a few years after 1861 the former name was subjected to publicity and ridicule when the hippocampus minor became the centre of a dispute over human evolution
Human evolution
Human evolution refers to the evolutionary history of the genus Homo, including the emergence of Homo sapiens as a distinct species and as a unique category of hominids and mammals...
between Thomas Henry Huxley and Richard Owen
Richard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
, satirised as the Great Hippocampus Question
Great Hippocampus Question
The Great Hippocampus Question was a 19th century scientific controversy about the anatomy of apes and human uniqueness. The dispute between Thomas Henry Huxley and Richard Owen became central to the scientific debate on human evolution that followed Charles Darwin's publication of On the Origin of...
. The term hippocampus minor fell from use in anatomy textbooks, and was officially removed in the Nomina Anatomica
Nomina Anatomica
In the late nineteenth century some 50,000 terms for various body parts were in use. The same structures were described by different names, depending on the anatomist’s school and national tradition. Vernacular translations of Latin and Greek, as well as various eponymous terms, were barriers to...
of 1895, but still featured in the Encyclopædia Britannica
Encyclopædia Britannica
The Encyclopædia Britannica , published by Encyclopædia Britannica, Inc., is a general knowledge English-language encyclopaedia that is available in print, as a DVD, and on the Internet. It is written and continuously updated by about 100 full-time editors and more than 4,000 expert...
of 1926, and appeared in general dictionaries as late as 1957.