OSTEOLOGY AND SYNDESMOLOGY. 31 
(pl. 128, fig. 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 bone (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 pistforme 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 the 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 uneiform 
bone (fig. 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 bones belong to the class of long bones. They are five 
in number (jig. 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 liga- 
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 bones. 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 Ingaments of the Superior Katremittes. 
The ligaments of the superior extremities comprise, 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-CLAVICULAR ARTICULATION. This articulation (pl. 125, figs. 
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 from the end of the cla- 
ICONOGRAPHIC ENCYCLOP£DIA.—VOl, II. 47 737 
