168 
MR. TOYNBEE ON THE ORGANIZATION AND NUTRITION 
demi ligne a une ligne, mais qui s’arretent toujours dans le point precis, ou la syno- 
viale cesse elle meme d’etre indistincte.” 
The arteries passing between the synovial membrane and the articular cartilage 
may be considered as the terminal branches of the articular vessels. 
Before they reach the articular cartilage they are but laxly covered by the synovial 
membrane, but at the border of the cartilage they are firmly bound down to it by the 
very small quantity of dense cellular tissue existing between them. It is difficult to 
state generally at what period of foetal existence the vessels, which have been spoken 
of in the first stage as forming convolutions around the joints, are prolonged upon its 
surface, and I can only here give the result of my investigations upon the subjects 
which I have been able to inject and examine. 
I have studied with care the stages by which these vessels are prolonged upon the 
head of the os femoris at the point where the ligamentum teres is attached. 
At between the third and fourth months of foetal life, these vessels are simply a mass 
of delicate convolutions situated beneath the synovial membrane ; at the fifth month 
these convolutions are somewhat unravelled, so as to extend over the surface of the 
cartilage to the distance of about half a line (Plate XIII. fig. 11.) ; and at between the 
seventh and eighth months they are drawn out and prolonged to the distance of a 
line and a half, Plate XIV. fig. 1. At this stage, these vessels consist of arteries of 
considerable size, which radiate in a straight course from the attachment of the 
ligamentum teres. They give off but few branches, and, previous to terminating, 
they divide and subdivide, but do not diminish much in size. They terminate by 
turning and forming loops with the small veins. Subsequent to the eighth month, 
these vessels begin to recede in their course ; and at birth, and the periods sub- 
sequent to it, they are again found to be gathered immediately around the point of 
attachment of the ligamentum teres. After these vessels have receded, the posi- 
tion they occupied at the more early periods may be for some time detected by the 
white aspect of the cellular tissue between the cartilage and the synovial membrane. 
In the knee-joint of the human foetus of five months, these vessels extend to a con- 
siderable distance over the surface of the articular cartilage, and in the foetus at 
birth, although they have receded considerably, they still occupy the inferior surface 
of the articular cartilage (Plate XIV. fig. 2.) ; in adult age they have entirely receded 
from it. 
These vessels in the knee-joint have a different mode of distribution from those 
above-mentioned in the hip. The arteries take a straight direction towards the 
centre of the articulation, and in their course they give off small branches, which, in 
the space between them, form a delicate network, and communicate with small veins. 
These arteries terminate either by turning in their course and forming broad loops 
with the venous radicles, or they empty themselves into a single vessel from which 
the veins arise, Plate XIV. fig. 2. 
