Karl Pearson and Adelaide G. Davin 
153 
(b) In man only a single fabella occasionally, and this on the lateral condyle. 
(c) A sesamoid in the tendon of the popliteus (which we term the cyamella 
lateralis) in the orang, but no fabellae. 
(d) No ci/aviella lateralis in man, but it does occur in baboons, dogs, foxes, 
cats, etc. 
Most of the above statements of Camper's can be confirmed, but there are 
certain exceptions, notably the cyamella lateralis, the sesamoid of the popliteal 
tendon, has been found in man, but it is very rare. Thus while it required 14 
centuries after Galen to establish the existence of the first two sesamoids of the 
knee-joint, the fabellae, in man and nearly 250 years after Vesalius to I'each the 
third sesamoid, the cyamella lateralis, in the orang, it took 80 years after Camper 
to establish the cyamella as an occasional anomaly in man. Such is the slow growth 
of scientific knowledge as evidenced in a single anatomical detail like the present. 
It must not, however, be supposed that with this rapid increase of knowledge in 
the last years of the 18th century, the 19th century would see rapid progress in 
our anatomical knowledge of the knee-joint. On the contrary the inertia and 
follow-the-other-fellow policy of the first half of the 18th century reappears in the 
19th. 
Cloquet in 1816 {Traite d'anatomie descriptive, Paris, I, p. 205) assures us that 
the fabellae appear fairly persistently on both condyles of the femur in man. 
Bourgery {Traite complet de I'anatomie, Paris, 1831, ii, p. 103) after describing 
the M. gastrocnemitis continues : 
Paj'fois chez les vieillards des os sesamoides se developpent dans leurs tendons femoraux, 
surtout dans celiii du jumcau interne (!). 
Indeed no treatise of anatomy could be complete without these "vieillards"; we 
have followed them through the centuries. The doubting Thomas, however, is always 
with us. Sappey as late as 1876 (Traitd d'anatomie descriptive, Paris, II, p. 430) 
denies the very existence of fabellae in man ! Even the modern English text- books 
of anatomy often do not exhibit a knowledge of the sesamoid of the knee-joint 
comparable with that of Eustachius, or as suggestive as the remark in Humphry 
(A Treatise on the Human Skeleton, 1858, p. 537): 
Where this band (posterior ligament of the kneQ-ynnt = Ug. popliteum cnict. ah semi-memh'anoso) 
joins the gastrocnemius upon the outer condyle of the femur is commonly a thick mass of fibrous 
tissue and sometimes a sesamoide Ijone (PI. 51, Fig. 2d*) is developed. 
Humphry (see our Plate IV, Fig. 7) is clearly adding to the accumulating 
knowledge of the mass of muscular attachments associated with the lateral fabella ; 
* This is we think the fiftJi representation of a fabella. Gruber (Gruber, p. 7) sngRests that 
Weitbrecht (Sijndesmolonia, 1742, Fig. 57, h) shows & fabella : "hat es vom Ursprunge bedeutend eutferut 
(etwas 2 cent.) im Gastrocnemius externus abgebildet, aber nn Texte nicht beneichnet." Pfitx.ner (Bibl. 
Pfitzner, S. 7-58) denies this. It is possible that Weitbi echt or his artist indicated something they did 
not understand, but the plate is too obscure to allow us to come to any conclusion whatever, and as 
Weitbrecht does not refer to the point in his text, the matter is not of the slightest real importance. 
There could not be another rediscovery of the fabella in 1742 ! 
