![]() ![]() Based on the anatomy of human and chimpanzee hand muscles and the positions of their attachment to individual bones, they have been able to establish a series of parameters that clearly distinguish the morphological and probably functional characteristics of the thumbs of these living primates.Ĭomplete sets of thumb bones from four Neanderthal skeletons show that they were significantly, but only slightly, different from anatomically modern humans. Biomechanics of the human thumb and the evolution of dexterity. The critical muscle for opposable thumbs is known as the Opponens pollicis (the Latin for thumb is Digitus pollex) a small triangular muscle that operates in conjunction with three others (with pollicis in their Latin names).įotios Karakostis and six colleagues from German, Swiss and Greek universities have devised software that can model muscles in 3-D (F.A. But that become increasingly difficult for the small-scale and intricate attachments in hands. It has become commonplace to reconstruct faces and even whole bodies from fairly complete skeletal remains by modelling musculature from the positioning and shape of the points of attachment of muscles to bone. The key lies in the muscles that operate them. Simply comparing the shapes of fossilised bones of fingers and thumbs with those of modern humans and other living primates has, so far, not proved capable of resolving with certainty which hominin groups either did or did not have opposable thumbs. The main muscles that control the movements of modern human fingers and thumb (Credit: Wikipedia) Whichever hominin had evolved opposable thumbs, their potential would have given them a considerable advantage over those that hadn’t. Complete fossil hands are rare, as are feet, but a number have been found more or less complete. Being made of many bones disarticulated hands are a lot more fragile than long bones or those of the skull. To do that, as most of us are aware, the tip of the thumb must be capable of touching the tips of all four fingers an opposable thumb is essential for the ‘precision grip’.īeing able to tell when opposable thumbs evolve depends, of course, on finding hand-bone fossils. The first makers of sophisticated stone tools must have been able to grip between fingers and thumb to manipulate the materials from which they were made and to perform the various stages in creating a razor sharp edge. At a desktop keyboard, most of us don’t use thumbs very much, unless we have mastered fast touch typing, but for a huge variety of manual tasks thumbs are essential. Since the appearance of smart phones and the explosion of social media our thumbs have found a new niche typing while holding a mobile. ![]() ( 1 Comment ) By Steve Drury First PUBLISHED ON February 9, 2021. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |