THE LIMB IN SECTION 37 



placed behind this muscle and the flexor metacarpi internus, is the 

 flexor metacarpi medius. In front of the flexor perforatus and the 

 flexor metacarpi medius are the two remaining divisions of the flexor 

 perforans. 



A transverse section across the metacarpal region is shown in Plate 

 X. The section was taken midway between the knee and the fetlock. 

 The greater part of the plate is occupied by the large metacarpal bone, 

 which is somewhat ellipitical in outline, being slightly compressed from 

 before to behind. Lying on the anterior aspect of this bone, and slightly 

 to the outside of the middle line, is the tendon of the extensor pedis, and 

 on the outer side of this again is the tendon of the extensor suffraginis. 

 Articulated postero-externally to the large metacarpal bone are the outer 

 and inner small metacarpals, sections of which are approximately tri- 

 angular in outline. Between the inner surfaces of the small metacarpals 

 and the posterior surface of the large metacarpal there is formed a 

 channel in which the suspensory ligament is placed. 



Two small arteries will be found to be placed in the grooves formed 

 anteriorly between the large and small metacarpal bones. These are the 

 external and internal dorsal interosseous vessels. In the angles formed 

 posteriorly between the large and small metacarpals we find the two 

 palmar interosseous arteries, near the inner of which is the deep meta- 

 carpal vein. The three vessels just mentioned are related posteriorly to 

 the suspensory ligament. 



Posteriorly placed to the suspensory ligament is the tendon of the 

 deep flexor of the digit, which will be observed to have a greater antero- 

 posterior dimension than the ligament although its transverse axis is 

 not so great. On the edges of the perforans tendon are the external 

 and internal plantar nerves. In front of the internal plantar nerve is 

 the large metacarpal artery, anterior to which is the internal metacarpal 

 vein. A small artery which descends from the subcarpal arch is found 

 in front of the external plantar nerve, and slightly in front of this again 

 is the external metacarpal vein. 



