Metric dimensions of the proximal phalanges of the human hand and their relationship to side, position, and asymmetry

The anatomy of the proximal phalanges of the human hand has been widely described. Nevertheless, when consulting osteology and anatomy publications, the general opinion of researchers is that siding and allocating the proximal phalanges with regard to finger position is difficult, if not impossible. We provide morphological criteria for determining the side of the proximal phalanges and a metric means of allocating a phalanx to a specific finger. This paper also quantifies the absolute and directional asymmetry found in phalanges within this sample. The sample studied consists of three groups, one modern and two archaeological. To investigate these, three measurements were taken—maximum length, maximum width at the base and maximum width at the head. It was found that phalanges could be assigned correctly to the side and finger of origin in 100% of the cases when the five phalanges of a given hand were present, and that this result dropped to 92% when allocating isolated phalanges. The means of the measurements taken were larger in the modern group and a constant relationship between the greater basal width of the second and the fourth proximal phalanges was found.