196 THE METACARPUS. 



the metacarpal bones, appears like the side of an arch, which 

 is partly induced by the wedge-like form of the two bones in 

 the centre ; viz., the trapezoides, and the magnum. When 

 the hand hangs b^ the side, and the palm is forward, all of this 

 surface presents downwards, except that portion of it which is 

 fermed by the trapezium. This bone is placed obliquely 

 between the two rows, and its surface for supporting the thumb 

 presents obliquely downwards and outwards. 



The trapezoides supports the fore-finger, the magnum the 

 middle finger. 



The scaphoides and the trapezium are very prominent at 

 the external side of the anterior concave surface of the car- 

 pus ; and the unciforme process, and the os pisiforme on the 

 internal. 



The Metacarpus, 



Consists of four bones, which sustain the finger. Each bone 

 IS long and round, with its ends larger than its body. The 

 upper end, which some call the base, is flat and oblong, in- 

 clining somewhat to the wedge-like form, without any con- 

 siderable head or cavity ; but it is, however, somewhat 

 hollowed for the articulation with the carpus. It is made flat 

 and smooth on the sides wdiere these bones are contiguous to 

 each other. Their bodies are flattened on the back part, 

 particularly below the middle, by tendons of the extensors of 

 the fingers. The anterior surface of these bodies is a little 

 convex, especially in their middle ; along which a sharp ridge 

 stands out, separating the musculi interossei placed on each 

 side of these bones, which are there made flat and plain by 

 these muscles. 



Their lower ends are raised into large oblong smooth heads, 

 whose greatest extent is forwards from the axis of the bone. 

 At the forepart of each side of the root of these heads, one or 

 two tubercles stand out, for fixing the ligaments that go from 

 one metacarpal bone to another, to preserve them from being 

 drawn asunder. Around the heads a rough ring may be 



