OSTEOLOGY AND SYNDESMOLOGY. 31 



{pi 123, ßg. 47 ') is smaller than the scaphoid. It also has four articular sur- 

 faces, for articulation with the radius, the os magnum, unciforme, scaphoides, 

 and cuneiforme. The cuneiforme or pyramidal hone {fig. 47') is wedge- 

 shaped, with the base looking outwards, and articulating with the lunare. 

 Its other articulations are to the unciforme and pisiforme. The pisiforme is 

 pea-shaped, and the smallest bone in the carpus, at the upper and inner part 

 of which it is placed. It articulates with the cuneiforme by a small circular 

 surface. The trapezium (fig. 47 ') is tlie most external of the second row 

 of the carpus ; it meets the scaphoid, the trapezoid, and the first and second 

 metacarpal bones. The trapezoides {fig. 47 ") is less in size than the latter ; 

 it articulates with the scaphoid, the trapezium, the magnum, and the second 

 metacarpal. The os magnum {fig. 47 ') is the largest bone in the wrist. It 

 supports the second, third, and fourth metacarpal bones, and joins the 

 scaphoid, the lunar, the trapezoid, and the unciform bones. The unciform 

 hone {fivg. 47 ") is next in size to the magnum. Situated at the lower and 

 inner part of the carpus, it articulates with the fourth and fifth metacarpal 

 bones ; also with the lunar, the magnum, and the cuneiform. 



The metacarpal hones belong to the class of long bones. They are five 

 in number {fig. 46'), and are nearly parallel with each other. All are con- 

 cave on the palmar surface, convex on the dorsal, and large at each extre- 

 mity. The posterior or carpal end is of rather irregular figure; the anterior 

 presents a round head. They are articulated anteriorly with the bases of 

 the first phalanges, and are flattened at the sides for the attachment of lio-a- 

 ments. 



The fingers are composed each of three phalanges, except the thumb, 

 which has but two. The first, or those nearest the carpus, are largest; next 

 come the middle ; the third row being the smallest. The posterior convex 

 surface of the last, or ungual phalanx, supports the nail. On the fore part 

 of the articulation between the metacarpal bones and the first phalanx of 

 the thumb, there are generally two small sesamoid hones. These, with 

 their analogues occurring in various situations in the body, do not properly 

 belong to the osseous system, being rather accessories to the tendons of 

 muscles. 



B. Articulations and Ligaments of the Sujyerior Extremities. 

 The ligaments of the superior extremities com.prise, 1. Those which 

 connect the clavicle with the sternum ; 2. Those connecting the clavicle 

 with the scapula; 3. Those proper to the scapula; 4. Those connecting the 

 humerus with the scapula; 5. Those connecting the bones of the elbow 

 joint; 6. Those of the wrist joint with those of the inferior radio-ulnar; 



7. Those of the metacarpus; 8. Those of the phalanges of the fingers; 

 9. Those connecting the metacarpus and the phalanges. 



1. Sterno-claviculak Articulation. This articulation {pi. 12ö,fi^'s. 



8, 9, 19) is arthrodial, and is secured by an anterior, posterior, inferior, and 

 inter-clavicular ligament, as also by an inter-articular cartilage and two 

 synovial membranes. 



The anterior sterno-clavicular ligament arises fi-om the end of the cla- 



ICONOGRAPHIC ENCYCLOPEDIA. — VOL. II. 47 737 



