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 26 On the Metacarpus

Why the metacarpal bones give way to muscles

But because these muscles are scarcely longer in their course than these bones, and the intervals are not so wide that an adequate mass of muscle can be placed in them, the metacarpal bones rightly appear concave on the inside [palmaris] where they form the palm,


page 121

1so that here also a portion of the muscles 29 may obtain a safe and fitting seat. But on the outer [dorsalis] side of the bones, the muscles do not protrude or go the least bit outside the convexity of the bones, making a surface that is level with the bones. Indeed, as we showed that the ulna and radius give way to the muscles tensioned upon them, so also we see metacarpal bones that are angular along their longitude and bulging handsomely along certain lines, without doubt on account of muscles 30 which are stretched out along them. 31 They are no less elegantly roughened on their upper [proximal] end in order to take an opportune insertion of the three muscles (one is L [m. flexor carpi radialis] in the 3rd table of muscles, another L [m. extensor carpi radialis] in the 11th, the other L [m. extensor carpi ulnaris] in the 9th) that flex 32 the carpus. This is not the only similarity of the metacarpals with the radius and ulna; they also possess a long cavity inside [cavitas medullaris] (like the one shown at D in the fig. inserted in ch.1 illustrates) suitable to contain marrow. That the metacarpus is very justly formed of four bones is clearly shown by the four fingers that are steadied by them; the fifth [pollex] needed to be opposed to them, 33 so to speak, if the hand was to be a convenient instrument for grasping. But now it would be more fitting also to devote a special chapter to the fingers.



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 26 On the Metacarpus