CHAPTER III 



THE LIMB IN SECTION 



Much useful information may be gained by the careful study of a 

 longitudinal section of the knee. Such a section is illustrated in 

 Plate VIII., which presents the mesial face of the outer half of the 

 right knee, and in making the section the saw has passed through 

 the semilunar, magnum, and pisiform of the small carpal bones. 



The outline of the inferior articular surface of the radius presents 

 in its anterior half a rather shallow concavity and in its posterior 

 half a marked convexity. The outline of the latter encroaches to such 

 an extent upon the posterior aspect of the bone that it forms a semi- 

 circle. Correspondingly we have the upper articular surface of the 

 semilunar bone presenting a convexity anteriorly, and posteriorly a 

 concavity. The posterior extremity of this surface projects upwards in 

 a peak-like process which, in complete flexion of the knee, passes into 

 the depression at the back of the radius immediately above its articular 

 surface. To permit uninterrupted passage of this projecting piece 

 of bone into the depression mentioned the posterior common ligament 

 is attached to an osseous prominence above the depressed area. The 

 great range of movement which this particular carpal joint possesses 

 is due to the conformation more especially of the posterior half of the 

 articular surface of the upper row of carpal bones. 



The intercarpal transverse joint is illustrated by the outline of 

 the inferior articular surface of the semilunar bone and the upper 



