Torso The notably large adult clavicle specimen ATD6-50, assumed male based on absolute size, was estimated to have stood , mean of , based on the correlation among modern Indian people between clavicle length and stature. An adult radius (a forearm bone), ATD6-43, which could be male based on absolute size or female based on gracility, was estimated to have belonged to a tall individual based on the average of equations among several modern populations relating radial length to stature. Based on metatarsal (foot bone) length, a male is estimated to have stood and a female . These are all rather similar values. For comparison, Western European Neanderthal estimates average , and early European modern humans . The ankle joint is adapted for handling high stress, which may indicate a heavy, robust body plan, much like Neanderthals. Based on the relationship between human footprint length and body size, twelve Happisburgh prints that are preserved well enough to measure are consistent with individuals ranging from in stature, which may mean some of the trackmakers were children. By this logic, the three biggest footprints—equating to statures of , , and —ranged from in weight. Stature estimates for H. antecessor, H. heidelbergensis, and Neanderthals are roughly consistent with each other. Two atlases (the first neck vertebra) are known, which is exceptional as this bone is rarely discovered for archaic humans. They are indistinguishable from those of modern humans. For the axis (the second neck vertebra), the angle of the spinous process (jutting out from the vertebra) is about 19°, comparable with Neanderthals and modern humans, diverging from H. ergaster with a low angle of about 8°. The vertebral foramen (that houses the spinal cord) is on the narrow side compared to modern humans. The spine as a whole otherwise aligns with modern humans. There is one known (and incomplete) clavicle, ATD6-50, which is thick compared to those of modern humans. This may indicate H. antecessor had long and flattish (platycleidic) clavicles like other archaic humans. This would point to a broad chest. The proximal curvature (twisting of the bone on the side nearest the neck) in front view is on par with that of Neanderthals, but the distal curvature (on the shoulder side) is much more pronounced. The sternum is narrow. The acromion (that extends over the shoulder joint) is small compared to those of modern humans. The shoulder blade is similar to