Volume XIII 
JULY, 1921 
Nos. 2 AND 3 
ON THE SESAMOIDS OF THE KNEE-JOINT. 
By KARL PEARSON and ADELAIDE G. DAVIN. 
PART I. MAN. 
CONTENTS 
PAGE 
(1) Introductory .133 
(2) Origin of the term Sesamoid 138 
(3) History of the Sesamoids of the Knee-Joint. First Period — that of isolated 
Records of Anatomical Writers ........ 14.5 
(4) History of the Sesamoids of the Knee-Joint. Second Period — that of Mono- 
graphic Literature 1.5.5 
(5) Frequency of the Fabellae in Man 164 
(6) Skiagraphic Data for the Occurrence of the Sesamoids of the Knee-Joint in 
Man 168 
(7) Summary of our Knowledge as to the Sesamoids of the Knee-Joint in Man . 171 
(1) Introductory. 
During the course of recent work* on the femur of the primates undertaken in 
the Biometric Laboratory, much material accumulated bearing on the sesamoids of 
the knee-joint. It was found impossible to incorporate this in that work itself, and 
as it was very largely due to a third investigator it is only fitting that the paper 
should be not only published separately, but with a different authorship. Some of 
those acquainted with the literature of the subject may consider that all that is 
necessary to be known on such an apparently "small topic has been fully dealt with 
already in the voluminous memoirs of Gruberi" and Pfitzner;]:. Both of these 
memoirs have their individual excellences, but we still venture to think that they 
have no more exhausted the subject than we ourselves are likely to do. Indeed 
merely a resume of their work in a form easily accessible to English readers would 
be of service ; but we hope to have added at least something of value to it, having 
trusted to what we believe is the only safe method of research, namely the first- 
hand investigation of the phenomena themselves before starting any study of the 
observations and opinions of others§. 
* Pearson and Bell, A Study of the Lovgbones of the Enr/lish Skeleton. Part II, The Femur of Man, 
with special reference to the Piimate Femora, see p. .512. Drapers^ Compamj Research Memoirs, 
Cambridge University Press. 
t For the full title of Gruber's classical memoir (hereiuafter cited merely as Gruber) see our p. 156. 
X For the full title of Pfitzner's memoir (hereinafter cited merely as Pfitzner) see our p. 163. 
§ Some time may be lost by postponing the study of the literature of a topic uutil at least a late 
stage of one's own researches, but on the other hand a preliminary study will too often cheek one's own 
individual line of research either by emphasising others' methods of approach, as if they were the sole 
road-i to truth, or by crowding the mind with a mass of other people's details, often best described as 
debris. 
Biometrika xm 9 
