Karl Pearson and Adelaide G. Davin 
1(53 
while noteworthy, if he had started from other primates where both coexist, is not so 
remarkable when he started from the musculature in man, where both rarely coexist. 
The bulk of the remainder of Gruber's monograph is taken up with a dis- 
cussion of the fahellae in other living forms than man. He made a long study of 
the literature of comparative anatomy and added many observations of his own. 
To these mattei's we shall return in the following section of this memoir. 
Before we leave the topic of the locus of the fahella lateralis in man we 
think some study of our Plates I and II is desirable. In Plates I and II, Figs. 1, 4, 5 
represent the strange positions of the fabella provided by Trew, Heister, and 
Casserius. Fig. 4 gives the position as envisaged by Camper, while Fig. 5 first 
shows some daylight as cast on the subject by Humphry*. In Plate I, Fig. 3 we 
provide a copy of Gillette's representation. It is clearly a case of Locus II, the 
fabella, resting in a flat facet on the condyle. Plate VI, Figs. 14 and 1.5 give a 
knee-joint from the Dissecting-Room at University College, London, to which our 
attention was drawn by Dr D. E. Deny. It is again a case like Gillette's of a 
facet fabella. The facet lies somewhat high on the articular surface of the condyle. 
Plate V, Fig. 10 gives Gruber's representation of a sesamoid in the popliteal sulcus. 
Fig. 12 is a good representation from Gruber of a "Knotenpunkt " fabella. Plate IV, 
Fig. 9 is an illustration of the AI. impliteus biceps with the supernumer'ary head 
attached to the sesamoid; it also shows the short lateral ligament likewise attached 
and the relation to M. gastrocnemius extern.us. Plate V, Fig. 11 shows the relation- 
ship of the fabella to AI. plantaris as pointed out by Cheselden and Humphry, 
while Plate IV, Fig. 8 gives the only mesial ossicle observed by Gruber, an obviously 
pathological ossification as he states. 
We may say that both locus and muscular attachments had been fully studied 
as far as the lateral fabella is concerned by 1876. 
(c) Ffitzners Monograph. " Die Sesambeine des Menschen." Schwalbe's 
Morphologische Arbeiten, Bd. i. S. 517 — 7(j2, Jena, 1892. We have already referred 
to many points of Pfitzner's work (see our pp. 134, 137, 158). He rejected the 
intensive stress hypothesis and carried the subject a step beyond Gruber by 
asserting a vestigial rather than a " use " origin. Sesamoid bodies (hemisesamoids) 
which he considers develop in " faserigen Gewebe " are " Abortivzustande " of 
sesamoid bones (orthosesamoids), p. 571. He places the fabella lateralis on the 
top and edge of condyle (pp. 568 and 578) — a position in accord with some of 
Gruber's observations, but differing widely from our own skiagram series. Only 
in one case (p. 581) did Pfitzner find the fabella in a facet on the condyle, which 
he speaks of as being its original place. While Gruber uses the word " gleiten " 
= glide, for the action of fabella on articular surface of condyle, PHtzner states that 
the sesamoid is incapable of moving on the condyle (p. 548), although it is never 
united (verschmolzen) to the femur. 
* Gruber considers that Weitbrecht and Humphry first placed the \ateraA fuhi'l la in its true position. 
We have akeady (p. 153, footnote) referred to the grave doubts which arise about what the former intended. 
