THE LIMBS OF THE HOKSE 75 



end on the third metacarpal bone. The ligament is pierced by a short 

 canal containing the tendon of the extensor digiti quinti. 



Medial collateral ligament (ligamentum collaterale mediale). — The 

 medial collateral ligament has a concentrated origin from the projection 

 on the medial side of the end of the radius. By somewhat divergent 

 fibres it is attached to the radial carpal bone (scaphoid), first, second 

 and third carpal bones (trapezium, trapezoid, and magnum), and the 

 bases of the second and third metacarpal bones. The variable and 

 inconstant first carpal bone (trapezium) may be entirely embedded in 

 the ligament. 



The medial collateral ligament is continuous with the transverse 

 ligament of the carpus, and assists in the formation of a canal for the 

 tendon of the flexor carpi radialis. 



Of the short carpal ligaments the following are the most readily 

 dissected : — 



Dorsal ligaments (ligamenta intercarpea dorsalia) connect each 

 carpal bone to its neighbour in the same row. In addition, a double 

 band passes obliquely from the third carpal (magnum) to the third 

 metacarpal bone. This is of some importance in connection with the 

 absence of flexion in the carpometacarpal joint. 



Volar ligaments (ligamenta intercarpea volaria). — On the volar 

 (flexor) aspect of the joint there are four ligaments that are not 

 difficult to demonstrate. (1) From the radius to the radial carpal 

 bone (scaphoid). (2) From the radius to the intermediate carpal bone 

 (lunar). (3) From the radial carpal (scaphoid) to the second and third 

 carpal bones (trapezoid and magnum). (4) From the ulnar carpal 

 (cuneiform) to the third and fourth carpal (magnum and unciform) 

 bones. 



Interosseous ligaments (ligamenta intercarpea interossea) are attached 

 to the depressed areas on the opposed surfaces of the bones in the same 

 row ; and two of them connect the bones of the distal row with the 

 three metacarpals. 



The accessory carpal (pisiform) bone is held in position by four 

 ligaments. (1) A band from the radius. (2) A dorsal ligament 

 attached to the ulnar carpal (cuneiform) bone. (3) A strong ligament 

 divided into two limbs and connected with the fourth carpal (unciform) 

 and fourth metacarpal bone. (4) A volar band attached to the ulnar 

 carpal (cuneiform) and intermediate carpal (lunar) bones. 



The intermetacarpal articulation (articulatio intermetacarpea). 

 — The bases of the three metacarpal bones are provided with small, 

 smooth areas lubricated by the secretion of the synovial layer of the 

 carpal joint capsule. For the rest, the second and fourth bones are 



