Academic literature on the topic 'Second metacarpal'

Normally the metacarpals have an epiphysis at one end — distally for the second to fifth and proximally for the first. Pseudoepiphyses are notches or clefts that occur at the non-epiphyseal ends of bones where an epiphyseal plate would be expected and are common incidental findings in the metacarpals of the growing hand. We aimed to identify the prevalence of pseudoepiphyses on serial radiographs of 610 healthy asymptomatic children. Pseudoepiphyses in the form of notches or clefts were common, identified most often in the second metacarpal (15.25%), fifth metacarpal (7.21%), and third metacarpal (0.49%). Complete pseudoepiphyses, in which the cleft extended across the full width of the metacarpal, were seen in the first metacarpal (1.97%) and the second metacarpal (1.31%). Pseudoepiphyses are a normal variant of metacarpal ossification and should not be confused with fractures in skeletally immature patients.

Human hands, when compared to that of apes, have a series of adaptations to facilitate manipulation. Numerous studies have shown thatAustralopithecus afarensisandAu. africanusdisplay some of these adaptations, such as a longer thumb relative to the other fingers, asymmetric heads on the second and fifth metacarpals, and orientation of the second metacarpal joints with the trapezium and capitate away from the sagittal plane, while lacking others such as a very mobile fifth metacarpal, a styloid process on the third, and a flatter metacarpo-trapezium articulation, suggesting some adaptation to manipulation but more limited than in humans. This paper explores variation in metacarpal torsion, a trait said to enhance manipulation, in humans, apes, early australopithecines and specimens from Swartkrans. This study shows that humans are different from large apes in torsion of the third and fourth metacarpals. Humans are also characterized by wedge-shaped bases of the third and fourth metacarpals, making the metacarpal-base row very arched mediolaterally and placing the ulnar-most metacarpals in a position that facilitate opposition to the thumb in power or cradle grips. The third and fourth metacarpals ofAu. afarensisare very human-like, suggesting that the medial palm was already well adapted for these kinds of grips in that taxon.Au. africanuspresent a less clear human-like morphology, suggesting, perhaps, that the medial palm was less suited to human-like manipulation in that taxa than inAu. afarensis. Overall, this study supports previous studies onAu. afarensisandAu. africanusthat these taxa had derived hand morphology with some adaptation to human-like power and precision grips and support the hypothesis that dexterous hands largely predatedHomo.

AbstractMetacarpal sign is a diagnostic radiological finding for cases of gonadal dysgenesis, also reported to be associated in a number of other endocrine abnormalities. Technically, it refers to relative difference in the lengths of medial three metacarpals, with the fourth and fifth metacarpals being shorter than the third metacarpal. We incidentally came across three cases that have been mentioned in this report. The first case primarily came to notice because of short fourth and fifth metatarsals. Further evaluation revealed that he also had short fourth and fifth metacarpals. The second case had isolated short fifth metacarpal and was idiopathic. The third patient, a known case of idiopathic hypoparathyroid hormone deficiency, had a short third, fourth, and fifth metacarpal, which is an unreported skeletal phenotype. The latter two cases had slight variation from the classical description of metacarpal sign, and may be a part of still hidden spectrum of metacarpal phenotypes.

We present the results of fresh cadaver hand dissections and dye injection studies to help in raising a vascularized bone graft from the index or middle metacarpals based on the second dorsal metacarpal artery. This vascularized bone graft could be used for treating nonunion of the scaphoid and other carpal bones.

Allografts were used to replace excised bone segments affected by giant cell tumour of the hand in three patients. The tumour involved the second, third and fourth metacarpals and the capitate in one case; the first metacarpal and the trapezium in one, and the proximal phalanx of the index in one. All had histological confirmation of diagnosis. One patient had recurrence one year after marginal resection of his third metacarpal and required resection of the two adjacent metacarpals and the capitate. He had no recurrence two years after the secondary treatment. The other two had no recurrence at two and three years after their primary procedures. Their affected hands were functioning well.

Abstract Aim : The aim of the present study is to provide parameters of 2nd metacarpal bones for sex determination from Saurashtra populations. Material and method: Forty two pairs of 2nd metacarpal bones were measured and their dimensions were compared with the dimensions of Spanish and American white population. The mean, SD, t value and p value were calculated, and demarcating point method for sexual dimorphism was employed. Result : Mean interarticular length of 2nd metacarpal was higher in male as compared to female for both sides (right and left) and the difference was statistically highly significant. Mean anteroposterior width at base of 2nd metacarpal was higher in male as compared to female for both sides(right and left),but the difference was statistically insignificant for right side and statistically significant for left side. Conclusion: The present study showed that interarticular length and anteroposterior width at base of 2nd metacarpal are effective parameters for sex determination.

This anatomical study defines a safe zone for percutaneous or minimally invasive fixation of first metacarpal fractures in order to avoid injury of the superficial branch of the radial nerve and the dorsal branch of the radial artery. The courses of the nerve and artery branches were marked in 20 embalmed cadaver specimens. With computer-assisted surgical anatomy mapping, a large diversity in the anatomical patterns for the nerve and a consistent pattern for the artery were found. Based on these findings, we conclude that transfixation of the first and the second metacarpals with K-wires placed in the distal 75% of both the first and second metacarpals is the safest way to avoid damages to the nerve and artery branches during fracture fixation.

Le remodelage osseux est un processus qui permet le renouvellement du tissu osseux tout au long de la vie des individus (Toppets et al. 2004). Il est bien connu que le remodelage est influencé à la fois par l’environnement mécanique (charges, activités) et par les besoins métaboliques (Pearson et Lieberman 2004; Rosas et Martinez-Maza 2010). Cependant, les effets des charges mécaniques sur le remodelage osseux restent encore peu compris (Lad and al. 2016; Pfeiffer and al 2006). Cette étude a pour but d’évaluer les réponses microscopiques des os aux charges mécaniques. L’échantillon étudié correspond à des paires de seconds métacarpes, issues de deux populations d’origine géographique distinctes (n=103, 55 Euro-Canadiens et 48 Inuits). À partir de section en coupe provenant de la mi-diaphyse, les lames minces ont été analysées selon quatre quadrants anatomiques : antérieur, médial, postérieur et latéral. Afin de contrôler les facteurs non mécaniques qui influencent le remodelage (tels l’âge) l’asymétrie entre les paires des métacarpes est calculée pour toutes les variables étudiées. Les charges sont estimées par les valeurs d’asymétrie de trois variables biomécaniques macroscopiques : Imax, Imin et J. Les asymétries de la densité de population des ostéons (OPD), de l’aire moyenne des ostéons et des canaux de Havers furent calculées pour estimer la réponse osseuse microscopique. De plus, il fut testé l’effet de la densité de population des ostéons sur leur aire moyenne. Les résultats démontrent que la densité d’ostéons diminue pour certains groupes (chez les hommes de St Thomas, r = - 0,412 et les femmes Inuits r = -0,547), et que les aires moyennes des ostéons et des canaux de Havers augmentent dans le quadrant antérieur du métacarpe le plus chargé (chez St-Thomas r = 0,297). De plus, il existe une relation négative entre l’augmentation de la densité d’ostéons et leur aire moyenne, dans le quadrant postérieur des femmes de St Thomas (r = -0,496). En conclusion, les charges mécaniques ont un impact sur la microstructure de l’os, rendant possible l’étude des charges à travers l’analyse histomorphologique du tissu osseux.
Bone remodeling is the process by which the skeleton can be renewed throughout the life of individuals (Toppets and al. 2004). It is well known that bone remodeling is a function of both mechanical (loads, activities) and non-mechanical factors such as metabolic needs of the bone (Pierson and Lieberman 2004; Rosas and Martinez-Maza 2010). However, the effects of mechanical environment on bone remodeling still remain poorly understood (Lad and al. 2016; Pfeiffer and al. 2006). This study aims to evaluate the microscopic bone responses to mechanical loading. The sample analyzed represents pairs of second metacarpal from two genetically separated populations (n=103, 55 Euro-Canadiens and 48 Inuits). From mid-shaft sections, thin sections were analyzed using four anatomical quadrants: anterior, medial, posterior and lateral. In order to control the influence of non-mechanical factors on bone remodeling, the asymmetry between pairs of metacarpals is calculated for each variable studied. Mechanical loading is estimated from the asymmetry values of three macroscopic biomechanical variables: Imax, Imin and J. Besides, asymmetries of osteon population density (OPD), mean areas of osteons and Havers canals were measured to estimate the microscopic bone response. Furthermore, it was tested the effect of osteon population density on osteon area. Results show that osteon population density decreases in some groups (in St-Thomas men r = - 0,412 and Inuit women r = -0,547), and the mean area of osteon and Havers canals increase in the more loaded side (in St-Thomas r = 0,297). In addition, there is a negative relationship between increased density of osteons and their mean areas in the posterior quadrant in St-Thomas women (r = -0,496). In conclusion, mechanical loading seems to have an impact on bone microstructure, making possible the inference of mechanical loadings through the study of bone histomorphology.