358 THE ARTICULATIONS. 



and cuneiform bones ; they are less strong than the dorsal, and placed very deeply 

 under the anterior ligament of the wrist. 



The Interosseous Ligaments (Fig. 251) are two narrow bundles of fibrous 

 tissue connecting the semilunar bone on one side with the scaphoid, and on the 

 other with the cuneiform. They are on a level with the superior surfaces of these 

 bones, and close the upper part of the spaces betAveen them. Their upper surfaces 

 are smooth, and form with the bones the convex articular surfaces of the wrist- 

 joint. 



The ligaments connecting the pisiform bone are 



Capsular. Two Palmar ligaments. 



The Capsular Ligament is a thin membrane which connects the pisiform bone 

 to the cuneiform. It is lined with a separate synovia! membrane. 



The two Palmar Ligaments are two strong fibrous bands which connect the 

 pisiform to the unciform, the piso-uncinate, and to the base of the fifth metacarpal 

 bone, the piso-metacarpal ligament (Fig. 248). 



2. ARTICULATIONS OF THE SECOND Row OF CARPAL BONES. 



These are also arthrodial joints. The articular surfaces are covered with carti- 

 lage, and connected by the following ligaments : 



Dorsal. Palmar. 



Three Interosseous. 



The Dorsal Ligaments extend transversely from one bone to another on the 

 dorsal surface, connecting the trapezium with the trapezoid, the trapezoid with 

 the os magnum, and the os magnum with the unciform. 



The Palmar Ligaments have a similar arrangement on the palmar surface. 



The three Interosseous Ligaments, much thicker than those of the first row, 

 are placed one between the os magnum and the unciform, a second between the 

 os magnum and the trapezoid, and a third between the trapezium and trapezoid. 

 The first of these is much the strongest, and the third is sometimes wanting. 

 Sometimes a slender interosseous band connects the os magnum and the scaphoid. 



3. A.RTICULATIONS OF THE TWO ROWS OF CARPAL BONES WITH EACH OTHER. 



The joint between the scaphoid, semilunar, and cuneiform, and the second row 

 of the carpus, or the mid-carpal joint, is made up of three distinct portions ; in the 

 centre the head of the os magnum and the superior margin of the unciform 

 articulate with the deep, cup-shaped cavity formed by the scaphoid and semilunar 

 bones, and constitute a sort of ball-and-socket joint. On the outer side the 

 trapezium and trapezoid articulate with the scaphoid, and on the inner side the 

 unciform articulates with the cuneiform, forming gliding joints. 



The ligaments are 



Anterior or Palmar. External Lateral. 



Posterior or Dorsal. Internal Lateral. 



The Anterior or Palmar Ligaments consist of short fibres, which pass, for the 

 most part, from the palmar surface of the bones of the first row to the front of the 

 os magnum. 



The Posterior or Dorsal Ligaments consist of short, irregular bundles of fibres 

 passing between the bones of the first and second row on the dorsal surface of the 

 carpus. 



The Lateral Ligaments are very short : they are placed, one on the radial, the 

 other on the ulnar side of the carpus ; the former, the stronger and more distinct, 

 connecting the scaphoid and trapezium bones, the latter the cuneiform and unciform ; 

 they are continuous with the lateral ligaments of the wrist-joint. 



The Synovial Membrane of the Carpus is very extensive : it passes from the 



