The Obłazowa 1 early modern human pollical phalanx and Late Pleistocene distal thumb proportions.

The human distal thumb phalanx from the earlier Upper Paleolithic of Obłazowa Cave, southern Poland, exhibits features of its palmar surface that align it morphologically principally with early modern humans. These aspects include the configurations of the proximal palmar fossa, the flexor pollicis longus tendon insertion, the proximal margin of the palmar apical tuft, and especially its low ulnar deviation angle. If it is assumed that it possessed the pollical phalangeal length proportions of an early modern human, it would exhibit modest base and tuft breadths. However, given Late Pleistocene archaic-modern contrasts in relative pollical phalanx lengths, the isolated nature of the phalanx prevents secure assessment of its radioulnar interphalangeal articular and apicaltuft hypertrophy. Similar constraints apply to the assessment of other Pleistocene Homo pollical phalanges.