The spelling of "circulus flava" may appear complex but using the International Phonetic Alphabet (IPA) can help understand its pronunciation. The word is spelled /ˈsɜːr.kjʊ.ləs ˈflɑː.və/ in IPA. The first syllable, "circulus," is pronounced with a soft "c" as in "sir" followed by "culus" pronounced like "cool" with an "us" ending. "Flava" is pronounced with a short "a" sound as in "cat" followed by "va" as in "father." Together, "circulus flava" means "yellow ring" in Latin.
Circulus flava is a Latin term used in anatomy to refer to a specific structure found within the brain. It is composed of a circular arrangement of yellowish or golden pigmented fibers located in the substantia nigra of the midbrain.
The term "circulus flava" is derived from the Latin words "circulus," meaning circle, and "flava," meaning yellow. This anatomical feature is often described as a distinctive discoloration due to the high concentration of the pigment melanin.
The circulus flava is primarily composed of nerve fibers and neurons that contain high levels of melanin. Melanin is a pigment that provides color to tissues and is particularly abundant in certain areas of the brain, such as the substantia nigra. The substantia nigra is involved in motor control, and its dysfunction is associated with movement disorders, such as Parkinson's disease.
The presence of circulus flava within the substantia nigra is thought to play a role in regulating the communication and coordination of neuronal signals related to motor function. While its exact function is still not completely understood, abnormalities in the circulus flava have been linked to neurological conditions such as Parkinson's disease, suggesting its importance in maintaining normal motor control.
In summary, circulus flava refers to a circular arrangement of yellowish fibers found in the substantia nigra of the midbrain, which is associated with motor control and may have a role in neurological disorders.
Vascular circle of the optic nerve, or of Haller, a network of branches of the short ciliary arteries on the sclera around the point of entrance of the optic nerve.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.