The term "calcar avis," which translates to "spur of the bird" in English, is a Latin phrase commonly used in anatomy to describe a projection on the inside of the brain. The word "calcar" is pronounced /ˈkæl.kɑr/ in IPA phonetic transcription, with the "c" sounding like a "k" and the second "a" as a short "a" sound. "Avis" is pronounced /ˈæ.vɪs/, with the "a" as a short "a" sound and the "v" as a "v" sound. Proper spelling is crucial in the field of anatomy to ensure clear communication and accurate understanding.
Calcar avis, also known as the calcar or calcarine sulcus, refers to a prominent sulcus or groove found on the medial aspect of the occipital lobe of the brain. It is primarily responsible for demarcating the boundaries of the primary visual cortex, also known as area 17 or V1.
The calcar avis runs parallel to and just above the calcarine fissure, separating the cuneus, which is the superior part of the occipital lobe, from the lingual gyrus, the inferior portion. This sulcus serves as a landmark indicating the division between the cortical representation of the upper and lower visual fields.
The calcar avis plays a crucial role in processing visual information received from the eyes. It serves as a guide for the organization of the primary visual cortex, allowing for the formation of a retinotopic map. This map corresponds to the precise arrangement of the visual field onto the surface of the cortex, with neighboring areas of the cortex representing neighboring sections of the visual field.
Understanding the calcar avis is essential in studying visual perception and different types of visual processing deficits. Researchers and clinicians often rely on mapping techniques, such as functional magnetic resonance imaging (fMRI), to accurately identify and study the calcarine sulcus in individuals.
Hippocampus minor, the lower of two elevations on the inner wall of the posterior horn of the lateral ventricle of the brain, caused by the proximity of the bottom of the calcarine fissure.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "calcar avis" is derived from Latin. "Calcar" means "a spur" or "a goad", and "avis" means "bird". The term literally translates to "the spur of a bird". This phrase was used in ancient Roman times to describe a particular formation in the human brain, which, upon dissection, resembled a spur or a spur-like structure. It is believed that the name arose due to the shape and location of this brain structure, which resembled the spurs found on the legs of certain birds.