An anatomical variation, anatomical variant, or anatomical variability is a presentation of body structure with morphological features different from those that are typically described in the majority of individuals. Anatomical variations are categorized into three types including morphometric (size or shape), consistency (present or absent), and spatial (proximal/distal or right/left).[1]
Variations are seen as normal in the sense that they are found consistently among different individuals, are mostly without symptoms, and are termed anatomical variations rather than abnormalities.[2]
Anatomical variations are mainly caused by genetics and may vary considerably between different populations. The rate of variation considerably differs between single organs, particularly in muscles.[2] Knowledge of anatomical variations is important in order to distinguish them from pathological conditions.
A very early paper published in 1898, presented anatomic variations to have a wide range and significance,[3] and before the use of X-ray technology, anatomic variations were mostly only found on cadaver studies. The use of imaging techniques have defined many such variations.[4]
Some variations are found in different species such as polydactyly, having more than the usual number of digits.
^Cunningham, DJ (October 1898). "The Significance of Anatomical Variations". Journal of Anatomy and Physiology. 33 (Pt 1): 1–9. PMC 1327970. PMID 17232348.
^Bell, Daniel J. "Anatomical variants | Radiology Reference Article | Radiopaedia.org". Radiopaedia.
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An anatomicalvariation, anatomical variant, or anatomical variability is a presentation of body structure with morphological features different from...
This article lists anatomicalvariations that are not deemed inherently pathological. Cervical rib Fabella Foramen tympanicum Supracondylar process of...
Anatomical terminology is a form of scientific terminology used by anatomists, zoologists, and health professionals such as doctors, physicians, and pharmacists...
Retrieved 12 March 2013. Standring, Susan (2021). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42nd ed.). [New York]: Elsavier. ISBN 978-0-7020-7707-4...
found in the same zone of the inferior vena cava. The most common anatomicalvariation is a persistent left superior vena cava. In persons with a persistent...
PMID 31424888, retrieved 2022-04-26 Standring, Susan (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York. p. 398. ISBN 978-0-7020-7707-4...
area on which the operation is performed is so close to the eye. An anatomicalvariation in humans occurs in the creases and folds of the upper eyelid. An...
in discussing anatomicalvariation. Entepicondylar foramen p. 212 Anatomy Atlases: Illustrated Encyclopedia of Human AnatomicVariation: Opus V: Skeletal...
note, the sphenoid sinus should be distinguished from an Onodi cell, an anatomic variant that is the posterior-most ethmoidal air cell. Onodi cells typically...
of Gray's Anatomy (1918) Standring, Susan (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York. p. 697. ISBN 978-0-7020-7707-4...
a high rejection rate, and is not possible for all women due to anatomicalvariation. If the flesh above the clitoris where the outer labia meet is fleshy...
causes the hymen to change in appearance and become very elastic. Normal variations of the post-pubertal hymen range from thin and stretchy to thick and somewhat...
behind the lateral condyle of the femur. It is an accessory bone, an anatomicalvariation present in 39% of humans. Rarely, there are two or three of these...
Asteri, T.; Sountoulides, P.; Vlasis, K.; Tsikaras, P. (2008). "Anatomicalvariation of left internal jugular vein". European Journal of Anaesthesiology...
Considerable anatomicvariation exists in the circle of Willis, with classic anatomy seen only in about one-third of people. In one common variation the proximal...
Abdala; et al. (Jul 2017). "On the presence of the patella in frogs". The Anatomical Record. 300 (10): 1747–1755. doi:10.1002/ar.23629. PMID 28667673. New...
to this vertebra. Also a cervical rib can develop from C7 as an anatomicalvariation. The term cervicothoracic is often used to refer to the cervical...
the azygos vein" (arcus venae azygos) is an important anatomic landmark. As an anatomicalvariation in 1–2% of the population, the arch can be displaced...
(even accounting for developmental stage) owing to anatomicalvariations. The most common variations include sutural (wormian) bones, which are located...
less than one per year, were reported in scientific literature. An anatomicalvariation can occur, known as a Phrygian cap, which is an innocuous fold in...
phalanges(10), intermediate phalanges (8) and distal phalanges (10). Through anatomicalvariation, the skeleton may have an accessory bone. Examples include sutural...
Shane (May 2016). Bergmans's Comprehensive Encyclopedia of Human AnatomicVariation. John Wiley & Sons. p. 1113. ISBN 978-1-118-43035-4. Rea, Paul (2015)...
The accessory nail of the fifth toe, also known as petaloid toenail, is a physical trait of the small toe, where a minuscule "sixth toenail" is present...
adults, its position is lower. A high-rising epiglottis is a normal anatomicalvariation, visible during an examination of the mouth. It does not cause any...
has assisted in the classification of animals. The first specifically anatomical investigation separate from a surgical or medical procedure is associated...
include trauma to the gluteal muscle, spasms of the piriformis muscle, anatomicalvariation, or an overuse injury. Few cases in athletics, however, have been...
In human anatomy, an azygos lobe is a normal anatomicalvariation of the upper lobe of the right lung. It is seen in 0.3% of the population. Embryologically...
testicular and ovarian aspects. In humans, ovotestes are an infrequent anatomicalvariation associated with gonadal dysgenesis. The only mammals where ovotestes...
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