Lower arm bones & ligaments. Historical anatomical artwork of lower arm bones (yellow) and ligaments (pale blue). Ligaments are bands of fibrous tissue that hold bones together at joints. The lower arm contains the ulna and radius bones, and is shown from the front (upper left) and behind (upper right, ulna at left). These join with the humerus (upper arm bone) at the elbow, seen down centre in four views/positions (from top): inner side; outer side; flexed, from behind; extended, from front. The wrist joint is seen from the inner side (ulna at top, lower right) and the outer side (radius at top, lower right). From The Bones and Ligaments of the Human Body (Ed. Jones Quain, London, 1842).