Radius (bone) ulna (center of the circle) to the edge of the radius (the circle). The ulna acts as the center point to the circle because when the arm is rotated the ulna does not move. In four-legged animals, the radius is the main load-bearing bone of the lower forelimb. Its structure is similar in most terrestrial tetrapods, but it may be fused with the ulna in some mammals (such as horses) and reduced or modified in animals with flippers or vestigial forelimbs. Radius (bone) The radius or radial bone is one of the two large bones of the forearm, the other
Hamate bone Wrist". The calcification of the unciform bone is seen on X-rays during puberty and is sometimes used in orthodontics to determine if an adolescent patient is suitable for orthognathic intervention (i.e. before or at their growth spurt). The etymology derives from the Latin "hamatus" "hooked," from "hamus" which means "hook". Hamate bone The hamate bone or unciform bone (from Latin "uncus", "hook") is a bone in the human wrist readily distinguishable by its wedge shape and a hook-like process ("hamulus") projecting from its palmar surface. The hamate is an irregularly shaped carpal bone found within the hand. The hamate is