Abstract:A single right fifth metatarsal found in Tomb 1 at Peligroso, Belize exhibited a small deformity in the form of a small (7 mm) accessory digit emanating from the plantar surface at mid-shaft. This Type A postaxial polydactyly is the first archaeological example of polydactyly reported for Mesoamerica. Polydactyly is one of the more commonly reported morphological anomalies and thus its appearance in Maya populations would have been prevalent enough to demand explanation. A review of related terminology in pert… Show more
“…Although polydactyly is not rare, and can be traced back at least 1000 years 10 , only its genetics has, until now, been studied. This may in part be due to the belief that supernumerary fingers represent a malformation and are not useful, thus are generally removed at a young age.…”
Section: Discussionmentioning
confidence: 99%
“…1). Polydactyly, the congenital physical anomaly of hands with more than five fingers is not rare in humans, with an incidence of around 0.2% 9 and archeology has demonstrated the presence of polydactyly individuals already in the mesoamerican civilization 10 . However, supernumerary fingers are often removed at birth 11 as they are deemed not useful and are often not fully developed.Fig.…”
Neurotechnology attempts to develop supernumerary limbs, but can the human brain deal with the complexity to control an extra limb and yield advantages from it? Here, we analyzed the neuromechanics and manipulation abilities of two polydactyly subjects who each possess six fingers on their hands. Anatomical MRI of the supernumerary finger (SF) revealed that it is actuated by extra muscles and nerves, and fMRI identified a distinct cortical representation of the SF. In both subjects, the SF was able to move independently from the other fingers. Polydactyly subjects were able to coordinate the SF with their other fingers for more complex movements than five fingered subjects, and so carry out with only one hand tasks normally requiring two hands. These results demonstrate that a body with significantly more degrees-of-freedom can be controlled by the human nervous system without causing motor deficits or impairments and can instead provide superior manipulation abilities.
“…Although polydactyly is not rare, and can be traced back at least 1000 years 10 , only its genetics has, until now, been studied. This may in part be due to the belief that supernumerary fingers represent a malformation and are not useful, thus are generally removed at a young age.…”
Section: Discussionmentioning
confidence: 99%
“…1). Polydactyly, the congenital physical anomaly of hands with more than five fingers is not rare in humans, with an incidence of around 0.2% 9 and archeology has demonstrated the presence of polydactyly individuals already in the mesoamerican civilization 10 . However, supernumerary fingers are often removed at birth 11 as they are deemed not useful and are often not fully developed.Fig.…”
Neurotechnology attempts to develop supernumerary limbs, but can the human brain deal with the complexity to control an extra limb and yield advantages from it? Here, we analyzed the neuromechanics and manipulation abilities of two polydactyly subjects who each possess six fingers on their hands. Anatomical MRI of the supernumerary finger (SF) revealed that it is actuated by extra muscles and nerves, and fMRI identified a distinct cortical representation of the SF. In both subjects, the SF was able to move independently from the other fingers. Polydactyly subjects were able to coordinate the SF with their other fingers for more complex movements than five fingered subjects, and so carry out with only one hand tasks normally requiring two hands. These results demonstrate that a body with significantly more degrees-of-freedom can be controlled by the human nervous system without causing motor deficits or impairments and can instead provide superior manipulation abilities.
“…Remarkably, the incidence of this type is ten times higher in Negroid populations than Caucasoids, although this only concerns the pedunculated type (Woolf and Myrianthopoulos, ; Buck‐Gramcko, ). Archaeological reports of polydactyly (reviewed by Wrobel et al, ) are scarce, despite the rather high incidence of polydactylous conditions. This is no surprise with respect to the pedunculated type, which usually lacks osseous elements.…”
Most congenital conditions have low prevalence, but collectively they occur in a few percent of all live births. Congenital conditions are rarely encountered in anthropological studies, not least because many of them have no obvious effect on the skeleton. Here, we discuss two groups of congenital conditions that specifically affect the skeleton, either qualitatively or quantitatively. Skeletal dysplasias (osteochondrodysplasias) interfere with the histological formation, growth and maturation of skeletal tissues leading to diminished postural length, but the building plan of the body is unaffected. Well-known skeletal dysplasias represented in the archeological record include osteogenesis imperfecta and achondroplasia. Dysostoses, in contrast, interfere with the building plan of the body, leading to e.g. missing or extraskeletal elements, but the histology of the skeletal tissues is unaffected. Dysostoses can concern the extremities (e.g., oligodactyly and polydactyly), the vertebral column (e.g., homeotic and meristic anomalies), or the craniofacial region. Conditions pertaining to the cranial sutures, i.e., craniosynostoses, can be either skeletal dysplasias or dysostoses. Congenital conditions that are not harmful to the individual are known as anatomical variations, several of which have a high and population-specific prevalence that could potentially make them useful for determining ethnic origins. In individual cases, specific congenital conditions could be determinative in establishing identity, provided that ante-mortem registration of those conditions was ensured. Clin.
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