82 OS MAGNUM UNCIFORMK. 



into a body and head. The head is round for the greater part of 

 its extent, but is flattened on one side. The body is irregularly 

 quadrilateral, and presents four sides and a smooth extremity. Two 

 of the sides are rough, the one being square and flat the dorsal, 

 the other rounded and prominent the palmar ; the other two sides 

 are articular, the one being concave, the other convex. The 

 extremity is a triangular articular surface, divided into three facets. 

 If the bone be held perpendicularly, so that the articular extremity 

 look upwards and the broad dorsal surface backwards (towards the 

 holder), the concave articular surface will point to the hand to which 

 the bone belongs. 



Articulations. With seven bones ; by the rounded head, with the 

 cup formed by the scaphoid and semilunar bone ; by the side of the 

 convex surface, with the trapezoides ; by the concave surface, with 

 the unciforme ; and by the extremity, with the second, third, and 

 fourth m^tacarpal bones. 



Attachments. To the flexor brevis pollicis muscle. 

 The unciform.e is a triangular-shaped bone, remarkable for a long 

 and curved process, which projects from its palmar aspect. It pre- 

 sents five surfaces ; three articular, and two free. One of the 

 articular surfaces is divided by a slight ridge into two facets ; the 

 other two converge, and meet at a flattened angle.* One of the 

 free surfaces the dorsal is rough and triangular; the other 

 palmar, also triangular, but somewhat smaller, gives origin to the 

 unciform process. 



If the bone be held perpendicularly, so that the articular surface 

 with two facets look upwards, and the unciform process back- 

 wards (towards the holder), the concavity of the unciform process 

 will point to the hand to which the bone belongs. 



Articulations. With jive bones ; by the two facets on its base, 

 with the fourth and fifth metacarpal bones ; by the two lateral arti- 

 culating surfaces, with the magnum and cuneiforme ; and by the 

 flattened angle of its apex, with the semilunare. 



Attachments. To two muscles the adductor minimi digiti, and 

 flexor brevis minimi digiti ; and to the annular ligament. 



Devclopement. The bones of the carpus are each developed by 

 a single centre. 



The number of articulations which each bone of the carpus pre- 

 sents with surrounding bones, may be expressed in figures, which 

 will materially facilitate their recollection ; the number for the first 

 row is 5531, and for the second 4475. 



METACARPUS. The bones of thS metacarpus are five in number. 

 They are long bones, divisible into a head, shaft, and base. 



The head is rounded at the extremity, and flattened at each side, 

 for the insertion of strong ligaments; the shaft is prismoid, and 

 marked deeply on each side, for the attachment of the interossei 

 muscles; and the base is irregularly quadrilateral and rough, for 



* When the unciforme does not articulate with the semilunare, this angle is sharp. 



