THE BONES OF THE UPPER LIMB 



207 



Articulations. — Superiorly with the semilunar, sup ero -internally 

 with the cuneiform, mjeriorly with the fourth and filth metacarpal 

 bones, and externally with the os magnum. 



Unciform Process 



For 5 th 

 Metacarpal. 



Inferior Aspect 



Unciform Proce 



For 4th Metacarpal For 5th Metacarpal 



Fig. 120. — The Right Unciform Bone. 

 A, External View ; B, Supero-intemal View ; C, Inferior View. 



The carpus as a whole is narrower above than below. The dorsal 

 aspect is irregularly convex, and the dorsal surfaces of the bones of 

 the first row (exclusive of the pisiform) are narrow, but in the second 

 row they are broad, this being reversed on the palmar aspect. It 

 is to be noted that the postero-internal angles of the trapezium, 

 trapezoid, and os magnum are distinctly elongated. The palmar 

 aspect is rendered concave by the tuberosities of the scaphoid and 

 trapezium externally, and the pisiform bone and unciform process 

 internally. These projections give attachment to the anterior 

 annular ligament, which with the palmar concavity forms a fibro- 

 osseous canal for the passage of the flexor tendons and median 

 nerve. The superior aspect, which is directed backwards as well as 

 upwards, is convex, and articulates with the radius and triangular 

 interarticular fibro-cartilage. The inferior or metacarpal aspect is 

 somewhat undulating. The inferior surface of the first row is for 

 the most part deeply concave, but externally it is convex. The 

 superior surface of the second row is concavo-convex from without 

 inwards, the concavity being formed by the trapezium and trapezoid, 

 into which the scaphoid convexity above is received, whilst the con- 



