Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them] | Chapter 24 On the Bones of the Forearm: the Ulna and Radius

Smooth and rough surfaces on the length of the radius

Not far from the upper joint, where the neck (M in figs. 1-4, 9) of the radius is located, the radius puts forth a rough, blunt process (q in the same figs.) which faces the inner part of the forearm and provides a suitable place for insertion of the anterior of the muscles [m. biceps brachii] that flex the forearm. Moreover, in the remaining distance from the humerus to the wrist, the radius is not at all round and smooth. Along its lower portion it produces a sharp and quite prominent line [margo interosseus] (r, r, in figs. 1-4) which faces the third line [margo interosseus] of the ulna and admits the ligament [membrana interossea antebrachii] (T, V, S in the 7th table of muscles) that binds together both bones of the forearm like a very strong membrane where they stand apart. The outer side [facies anterior] of this line (s, s in figs. 1, 3), like the inner [facies posterior] (t, t in figs. 3, 4), 48 is also compressed and concave to make room for the muscles occupying the outer and inner portions of the forearm respectively. The inner side is rougher than the outer, because the muscle [m. flexor pollicis longus] that flexes the third bone of the thumb (h in the 6th table of muscles) takes a major portion of its origin from that side. The upper area of the radius opposite the line just described is nearly smooth and round, and near the midpoint of its length it is somewhat rough (u in figs. 2, 3, 4) so that two muscles can achieve a stronger insertion: one of them [m. supinator] (Q in the 7th table of muscles) is the shorter of the ones that supinate the radius, the other [m. pronator teres] (L in the 12th table of muscles, and then d, e) 49 the superior of those that pronate the radius. This roughness is particularly carved for the latter of these muscles because it makes a more sinewy than fleshy insertion 50 and it runs further along the bone.



Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them] | Chapter 24 On the Bones of the Forearm: the Ulna and Radius