40 



METACARPUS. 



Fig. 23. 



Scaphoid^ is on the radial side, and resembles a boat ; has a large 

 ' convex surface superiorly for the ra- 

 dius, and inferiorly a deep concavity 

 for the magnum. It articulates in 

 front with the trapezium and trape- 

 zoides, and on the inside with the 

 lunare. 



Lunare, of a crescentic figure, 

 has a convex surface superiorly for 

 the radius, and a concavity in front 

 for the magnum, articulates on the 

 inside with the cuneiform. 



Cuneiform. — Wedge-shaped, or 

 pyramidal. Inferiorly it articulates 

 with the unciform. Distinguished by 

 a circular facet on its palmar surface 

 for the pisiform. 



Fisiform. — Pea-like bone, forms 



one of the prominences in the palm 



of the hand, has the flexor carpi ulnaris muscle inserted into it, and 



has but one articular mark, which is for the cuneiform. It is the 



smallest bone of the carpus. 



Trapeziwni^ has the most surfaces and angles. The largest 

 articular surface is for the thumb ; two others, joining each other, 

 are for the scaphoid and trapezoides. On the palmar surface is a 

 ridge and a deep groove for the flexor carpi radial is tendon. 



Trapezoides., is the smallest bone of this row — is a four-sided 

 pyramid with its apex towards the palm ; its dorsal surface is the 

 base and inclines inwards. 



Magnmn. — The largest bone of the wrist. Has a rounded head 

 looking backwards ; the body is quadrilateral. 



Unciform. — Distinguished by a hook-like process resembling a 

 nail on its palmar surface, which gives origin to the flexor brevis 

 minimi digiti. 



METACARPUS 



Consists of five bones, each having a head, shaft, and base. 



The head is rounded, articulating with the phalanx; a roughness 

 on each side indicates the attachment of the lateral ligament. 



The ha&e is the superior extremity, rough, and quadrilateral, 

 having articular marks on the extremity and either side. 



The body or shaft is prismoid, having impressions on its sides for 

 the interossei muscles. 



First, is short and thick, for the thumb. Its base has but one 

 articular surface, and that is for the trapezium. Its head is not very 

 spherical, its palmar surface articulates with the sesamoid bones. 



