CHAPTER VI. 
which fcrves in the fcapula to make a larger fockct, and fuch a one as will 
alter its figure as the bone moves, for thcreafon I have mentioned in the 
loofe cartilages of the knee; for the head of the os humeri, not being an 
exadf portion of a fpherc, requires fuch a fockct, and the hard part of this 
ligament of the locket of the os innominatum makes the locket deeper 
than the femidiameter of the fockct, by which means the articulation is 
made fironger without any hindrance to motion, becanfc it will give way 
to the neck of the os femoris when it preffes again!! it; and the thigh bone 
being more difpofed to be dillocated upwards than any other way, the 
upper fide of this burfal ligament is made exceeding ftrong to prevent 
fuch an accident. From the lower edge of the acetabulum or fockct of 
the os innominatum arifes a ligament about an inch long called teres, or 
rotundum, (Tab. xxxix.) which length is neceflary for that quantity of 
motion which this joint has in human bodies; it alfo hinders the os femo¬ 
ris from difiocating upwards, but downwards it will fufter it to go far out 
of the fockct; but in brutes the head of the os femoris being oblong, and 
the cavity fuitable, there can be only a rotatory motion, which in the ef¬ 
fect will be very little more than that kind of motion which is called 
bending and extending; and this never removing the end of the head of 
the bone far in the fockct, a fiiort ligament is enough for it, and will bet¬ 
ter keep the bone in its place; and therefore it is that theirs is fo fhort. 
This ligament in men may alfo ferve to prefs the gland in the bottom of 
the acetabulum or focket. 
The ligaments of thofe joints which admit only of flexion and exten- 
fion, differ from the former in this, that they are much fhorter and ftrong- 
er at the fides of the joints, and thinner backward and forward. Befides 
thefe ligaments in the middle and back-part of the joint of the knee (Tab. 
xl.) are two very ftrong ligaments which arile from a procefs at the end of 
the tibia. They crofs each other in fuch a manner, as is beft to feeure the 
joint from being difplaced anyway; they alfo hinder the extenforsof the 
tibia from pulling that bone too far forwards, and are fo connected to the 
femilunar cartilages, as to move them as the joint moves; befides thefe 
in this joint is another lmall one, which arifes from the os femoris, and 
ends in the fatty membrane which it fupports. 
The bones of the carpus and tarfus (Tab.xxxviii. xl.) are tied together 
by ligaments running promifeuoufly upon their furfaces from one to ano¬ 
ther; which at the under fide of the tarfus are vaftly ftrong, becaufethey 
fupport the whole body; thefe ligaments together contain the mucus for 
all thofe joints. There is alfo to the carpus a ftrong ligament which runs 
