THE UPPER LIMB 423 



Wrist-Jofnt. — This joint is to be studied in the same way as the elbow-joint. 



Radlo-ulnar Joints. — The superior radio-uhiar joint has only the orbicular 

 or annular Ugament, and its synovial membrane is continuous with that of the 

 elbow-joint. The chief bond of union at the inferior radio-ulnar joint is the 

 triangular fibro-cartilage, which is to be carefully examined, along with the 

 sjTiovial membrane, which is called the membrana sacciformis. As regards 

 the intermediate connection between the radius and ulna, the interosseous 

 membrane is to be dissected, and its anterior and posterior relations studied. 

 The opening in it near its lower part for the posterior branch of the anterior 

 interosseous artery is to be shown. The obUque Ugament at the upper end 

 is to be examined, and between it and the upper border of the interosseous 

 membrane will be seen the interval for the passage of the posterior interosseous 

 vessels. The movements of pronation and supination are to receive close 

 attention, and the dissector is to make himself thoroughly famiUar with the 

 muscles concerned in these important movements. 



Carpal Joints. — The transverse carpal joint is to be dissected first, and the 

 ligaments and movements are to be studied. The pisiform joint is next to be 

 examined, and its capsular Ugament shown. The dorsal, palmar, and inter- 

 osseous Ugaments of the other three bones of the first row are next to be 

 examined, foUowed by those of the second row. The carpo-metacarpal joints 

 are to be studied, and special attention should be directed to the joint between 

 the trapezium and first metacarpal bone. The intermetacarpal (basal) joints 

 follow next. The deep transverse Ugament which connects the palmar aspects 

 of the heads of the four inner metacarpal bones has been already dissected. 

 The metacarpo-phalangeal joints, followed by the interphalangeal, are next to 

 be dissected. The strong anterior fibrous plate is to be noted, and the absence 

 of a dorsal Ugament, its place being taken by the extensor tendon. In the 

 metacarpo-phalangeal joint of the thumb no anterior fibrous plate will be found, 

 its place being taken by two sesamoid bones. Special attention is to be given 

 to the arrangement of the s\-novial membranes, from the inferior radio-ulnar 

 joint above, wth its membrana sacciformis, to the intermetacarpal (basal) 

 joints below. The number of these synovial membranes and the complexity 

 of that of the carpus are to be noted. 



