Anatomical normality and variability: Historical perspective and methodological considerations

Żytkowski, Andrzej; Tubbs, R. Shane; Iwanaga, Joe; Clarke, Edwin; Polguj, Michał; Wysiadecki, Grzegorz

doi:10.1016/j.tria.2020.100105

Cited by 83 publications

(83 citation statements)

References 20 publications

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“…Therefore, at last, we suggest that the FM's anatomic and morphometric evaluation showed a significant difference between various parameters, so further comparative studies were required. Repeated anatomical observations deepen existing knowledge, help overcome the subjective aspect in the description made by individual researchers, and can be useful for practitioners [29]. Round; G. Irregular; H. Egg-shaped.…”

Section: Discussionmentioning

confidence: 99%

A golden ratio for foramen magnum: an anatomical pilot study

et al. 2022

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Background: The foramen magnum (FM) is an important landmark because of its close relationship to key structures such as the brainstem and spinal cord, an extension of the medulla oblongata. Because of the similarity in their shape, the existence of a relationship between cranial length and anteroposterior diameter of the FM, and between cranial width and transverse diameter of the FM may reveal the magnificent harmony of the skull and FM. Based on this idea, we investigated the existence of this harmony in skulls that we used in our study. Materials and methods: In this study, 60 adult dry skulls belonging to the Turkish population were examined. The anteroposterior and transverse diameters of the foramen magnum and the length and width of the skull were measured. Measurements were made directly on the skull using a digital sliding caliper. New indices and ratios were applied with those measurements. Results: Our study suggests that FM width and FM length could be estimated by using the cranial length and cranial width measurements in the skull by accepting the mean of these coefficients (4.62) as the golden ratio. The average of the coefficients of cranial width to FM width ratio [4.62 ± 0.35 (95% CI: 4.52-4.70)] and the average of the coefficients of cranial length to the FM length ratio [4.62 ± 0.50 (95% CI): 4.49-4.76)] were found to be equal to each other. In order to check the accuracy of this hypothesis, FM width and FM lengths were estimated with the help of new equations. Conclusions: In the present study, the ratio between the anteroposterior and transverse diameters of both FM and the cranium was estimated at 4.62, indicating a magnificent harmony between cranial and subcranial structures. With this ratio, it is easy to estimate FM's size based on simple cranial measurements.

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Section: Discussionmentioning

confidence: 99%

A golden ratio for foramen magnum: an anatomical pilot study

et al. 2022

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“…The variation found in this case report constitutes an abnormal connection of the sympathetic chain that most likely arose during early embryonic development. While this finding appears to be extremely rare, it nonetheless results in an abnormal pattern of innervation from the lumbar sympathetic chain and could contribute to surgical complications during approaches to the lumbar spine [5,16,17].…”

Section: Discussionmentioning

confidence: 99%

Premature termination of the sympathetic chain

Mansour

Kulesza

2022

Folia Morphol

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The sympathetic chain serves to distribute visceral efferents and afferents over the entire body.The sympathetic chain courses from the base of the skull to the coccyx and sends branches to distribute along spinal nerves and a number of visceral nerves that distribute to cardiac muscle, smooth muscle and glands. During dissection of the posterior abdominal wall, we identified a rare variation of the sympathetic chain. In this subject, the sympathetic chain failed to send gray rami to the L2-4 spinal nerves and terminated by joining the S1 anterior ramus. Such a variation has only been reported once in the literature in 1895. We provide both schematic and photographic documentation of this variation and propose a number of possible circuits whereby visceral axons can reach their target despite these anatomical barriers.

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“…However, the craniocaudal shift changes were unclear due to the range of variation shown in a typical human lumbar plexus roots, where one additional or reduced thoracolumbar count was considered a typical variation. This issue on anatomical normality and variability have been deeply debated in the long history of anatomy [49]. One additional or reduced thoracolumbar count is often observed within the normal range, so each anatomical normality and variability may not be easy to identify among their overlapping variation based on this concept.…”

Section: Introductionmentioning

confidence: 99%

Does the phenotypic morphology of the human brachial plexus reflect the theoretical development of concomitant regulation in thoracolumbar spines and nerves?

2022

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Background: Experimental evidences identified that thoracolumbar mutants caused by Hox genes 7-10 mutants also involve a craniocaudal shift and/or the addition or reduction of segments of the limb plexus roots. This study investigated whether the theoretical concomitant shift of the brachial plexus roots in human different thoracolumbar counts is shared as confirmed in those of the human lumbosacral plexus. Material and methods:The phenotypic morphology of the brachial plexus and its arterial interaction on 20 sides of 10 atypical human thoracolumbar counts out of the 354 sides of the 177 cadavers, were compared with those of 52 sides of 26 cases in a typical human vertebral formula (7C_12T_5L_5S).Results: Regardless of the course and branching patterns of the axillary artery, our results showed that the main brachial plexus roots were composed of only five segments of the 5 th -9 th spinal nerves, with small contributions from the 4 th and/or 10 th nerves. This root composition is identical to a typical human thoracolumbar formula, and therefore, neither a craniocaudal shift nor additional/reduced main roots occurred in our thoracolumbar variants. Conclusions:Unlike the concomitant shift of the lumbosacral plexus roots, our present cases suggest that the phenotypic morphology of the human brachial plexus may be less likely to 1 show theoretical craniocaudal shifts, further data on the root changes in different vertebral formulae are needed for its accurate validation.

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Anatomical normality and variability: Historical perspective and methodological considerations

Cited by 83 publications

References 20 publications

A golden ratio for foramen magnum: an anatomical pilot study

A golden ratio for foramen magnum: an anatomical pilot study

Premature termination of the sympathetic chain

Does the phenotypic morphology of the human brachial plexus reflect the theoretical development of concomitant regulation in thoracolumbar spines and nerves?

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