all Homo with a typical human body plan, indicating H. antecessor was not as skilled a climber as non-human apes or pre-erectus species, but was capable of efficiently launching projectiles such as stones or spears. Limbs The incomplete radius, ATD6-43, was estimated to have measured . It is oddly long and straight for someone from so far north, reminiscent of the proportions seen in early modern humans and many people from tropical populations. This could be explained as retention of the ancestral long limbed tropical form, as opposed to Neanderthals who evolved shorter limbs. This could also indicate a high brachial index (radial to humeral length ratio). Compared to more recent human species, the cross section of the radial shaft is rather round and gracile throughout its length. Like archaic humans, the radial neck (near the elbow) is long, giving more leverage to the biceps brachii. Like modern humans and H. heidelbergensis, but unlike Neanderthals and more archaic hominins, the radial tuberosity (a bony knob jutting out just below the radial neck) is anteriorly placed (toward the front side when the arm is facing out). Like those of other archaic humans, the femur features a developed trochanteric fossa and posterior crest. These traits are highly variable among modern human populations. The two known kneecaps, ATD6-22 and ATD6-56, are subrectangular in shape as opposed to the more common subtriangular, although rather narrow like those of modern humans. They are quite small and thin, falling at the lower end for modern human females. The apex of the kneecap (the area that does not join to another bone) is not well developed, leaving little attachment for the patellar tendon. The medial (toward the midline) facet and lateral (toward the sides) facet for the knee joint are roughly the same size as each other in ATD6-56 and the medial is larger in ATD6-22, whereas the lateral is commonly larger in modern humans. The lateral facet encroaches onto a straight flat area as opposed to being limited to a defined vastus notch, an infrequent condition among any human species. The phalanges and metatarsals of the foot are comparable to those of later humans, but the big toe bone is rather robust, which could be related to how H. antecessor pushed off the ground. The ankle bone (talus) is exceptionally long and high as well as the facet where it connects with the leg (the trochlea),