164 
On the Sesamoids of the Knee Joiut 
Pfitzner is less dogmatic than Gruber as to the existence of a mesial fabella in 
man allowing a certain amount of weight to the records of Heister, Morgagni, 
Hyrtl and Macalister (see our p. 155), but he states that he has never seen it 
himself (p. 580). On the other hand he has always found it in dog, fox and hare, 
while in 52 cats he found the fabella lateralis always present, but the fabella 
mesialis was absent in 29 out of the 52 cases. 
Turning to the ci/amella lateralis, which Pfitzner describes as in the tendon of 
it/, popliteas and working on the curved continuation of the articular surface of the 
Gondylus lateralis tibiae, he states that it is constant in Felidae and Leporidae, and 
that he has himself once found it in a dog. He says that it has never been noticed 
in man. If we can trust the observations of Macalister, Krause and -Knott, and 
if we have not misinterpreted those of Gruber this statement is inaccurate 
(pp. 583 — 584). Lastly as for as we are aware Pfitzner is the only person who has 
recorded a cyamella mesialis, and this only in two cats (p. 584). He was unable 
to note the muscular attachments. We have gone through a considerable number 
of dog skeletons in the Biometric Laboratory, in which as a rule the fahellae are 
preserved, but have met with no cases of cyainellae being preserved. 
The literature of the sesamoids of man is fairly comprehensively treated by 
Pfitzner, and we have found his references very helpful in our search into the 
history of our knowledge of the sesamoids in man. We shall refer to his statistics 
of occurrence in man later. On the whole while Pfitzner's memoir is of great 
value — in particular he recognised the cyamella — it is not epoch-making in the 
sense of Gruber's. 
(5) Frequency of the Fabellae in Man. 
Putting aside the vague statements of the mediaeval anatomists we have five 
sources from which this frequency may be determined (i) Gruber, (ii)Ost, (iii ) Pfitzner, 
(iv) the Seventh Report of the Collective Investigation. Committee, (v) Skiagram 
Data. 
We can dismiss Ost at once ; his paper* is very brief and refers to only 30 cases 
in which he found a fabella five times or IB'?"/^ ; sex is not given. Pfitzner observed 
hemisesamoids or orthosesamoids in 30 out of 290 cases or in 10'34'"/^. He never 
met with a fabella mesialis. While Pfitzner presents little analysis of his cases 
Gruber provides a considerable amount, but it is occasionally far from clear as to 
what exactly he is referring to. 
Thus Gruber tells us (p. 70) that without regard to size or sex it appears in 
about i of the cases, i.e. 16"7''/„. On p. 26, however, he tells us that in 2340 
limbs he found it in 400 instances or l7"l7o- Paying regard to sex Gruber states, 
again on p. 70, that he found it in about of the male cases and ^ to | of the 
female; according to this the lateral fabella occurs in 207o of cases in man and 
* Ueber das Voikommen eines Sesambeines in den Ursprungssehnen des Gastrocnemius beim 
Menschen. Zcitschrift filr Anatomic und Entwickehingsgc^chichtc, Bd. ii, S. 309, Leipzig, 1881. 
