A N A T 
fore it is joined at both ends in the fame manner, which 
none of the bones of the thumb are. The third bone dif¬ 
fers notiiing from the defcription of the third bone of the 
thumb, excepting in the general diftinguifhing marks; and 
therefore the fecond and third phalanx of the fingers 
enjoy only flexion and extenfion. Ail the difference of 
the phalanges of the feveral fingers confifts in their magni¬ 
tude. The bones of the middle finger being tire longed 
and larged, thofe of the fore finger come next to that in 
thicknefs blit not in length, for thofe of the ring finger are 
a little longer. The little finger has the fmallelt bones. 
Which difppfition is the bed contrivance for holding the 
larged bodies ; becatife the longed fingers are applied to 
the middle^ larged periphery of inch fubdances as are of a 
fpherical figure. 
OF THE INFERIOR EXTREMITIES. 
The inferior extremities depend from the acetabula of the 
offa innominata ; and are commonly divided into three 
parts, viz. the thigh, leg, and foot. 
The thigh has only one bone, which is the longed in the 
body, and the larged and dronged of any of the cylindri¬ 
cal bones. The fituation of it is not perpendicular; for 
the lower end is inclined conliderabiy inwards ; io that 
the knees are almod contiguous, while there is a confider- 
able didance betwepn the thigh-bones above; which is of 
great ufe, fince fufficient Ipace is thereby left for the ex¬ 
ternal parts of generation, the two great cloacae of urine 
and faeces, and for the large thick mufcles that move the 
thigh inwards. At the fame time this fituation of the thigh¬ 
bones renders our progrefiion quicker, furer, draighter, 
and in lefs room ; for, had the knees been at a.greater dil- 
tance from each other, we mud have been obliged to de- 
feribe feme part of a circle with the trunk of our body in 
makin 0 ' a long bep; and, when one leg was raifed from 
the ground, our centre of gravity would have been too far 
from the bale of the other, and we fiiould eonfequently 
have been in danger of falling; fo that our heps would 
neither have been draight nor firm, nor would it have been 
poffible to walk in a narrow path, had our thigh-bones 
been otherwife placed. 
The upper end of the thigh-bone is not continued in a 
ftraight line with the body of it, but is fet oft obliquely in¬ 
wards and upwards, whereby the diftance between thefe 
two bones at their upper part is confiderably increafed. 
This end is formed into a large fmooth round head, which 
is the greater portion of a fphere unequally divided. To¬ 
wards hs lower internal part, a round rough fpongy pit is 
obfervable, where the ftrong ligament, commonly, but un- 
juftly, called the round one, is fixed, to be extended from 
thence to the lower internal part of the receiving cavity, 
where it is confiderably broader than near the head of the 
thigh-bone. The fmall part below' the head, called the 
cervix, of the os femoris, has a great many large holes, 
into which the fibres of the firong ligament, continued 
from the Capfular, enter, and are thereby firmly united to 
it • and round the root of the neck, where it rifes from the 
hones, a rough ridge is found, where the capfular ligament 
of the articulation itfelf is connected. Below the back- 
part of this root, the large unequal protuberance, called 
trochanter major , hands out ; the external convex part of 
•which is diftinguifhed into three different furfaces; where¬ 
of the one on the fore-part is fcabrous and rough, for the 
infertion of the glutaeus minimus ; the fuperior one is 
fmooth, and has the glutaeus medius inferted into it; and 
the one behind is made flat and fmooth, by the tendon of 
the glutaeus maxi mus palling over it. The upper edge of 
this procefs is (harp and pointed at its back-part, where the 
(flattens medius is fixed ; but forwards it is more obtufe, 
and has two fuperficial pits formed in it; into the fuperior 
of thefe the pyrifonnis is implanted, and the obturator in¬ 
terims and gemini are fixed into the lower one. From the 
hinomoft prominent part of this great trochanter, a rough 
ridge runs backwards and downwards, into which the qua- 
cratus is inlerted. In the deep hollow, at the internal 
O M Y_ 
upper fide of this ridge, the obturator externus is im¬ 
planted. More internally, a conoid procefs, called tro¬ 
chanter minor, rifes for the infertion of the mufculus pfoas 
and iliacus internus; and the pebtineus is implanted into 
a rough hollow below its internal root. The mufcles in¬ 
ferted into thofe two proceffes being the principal inftru- 
mentsof the rotatory motion of the thigh, have occafioned v 
the name of trochanters’ to be given to thofe proceffes. The 
tendons that are fixed into or pafs over the great tro¬ 
chanter, caufe bruifes, by falls on this part, to be attend¬ 
ed with great pain or weakness of the limb, which gene¬ 
rally remain long. The fore-part of the thigh-bone is a 
little flatted above by the beginning of the cruraeous muf- 
cle, as it is alfo below by the fame mufcle and the reftus. 
Its external furface is likewife made flat below by the 
vaflus externus, where it is leparated from the former by 
an obtufe ridge. The v A ft us internus depreffes a little the 
lower part of the internal furface. The pofterior concave 
furface has a ridge rifing in its middle, commonly called 
tinea afpera, into which the triceps is inlerted, and the 
ftiort head of the biceps flexor tibiae riles from it. At the 
upper part of it the medullary veffels enter, by a fmall 
hole that runs obliquely upwards. A little above which 
there is a rough folia, where the tendon of the glutaeus 
maximus is fixed. The lower end of the linea afpera di¬ 
vides into two, which defeend towards each (ide. The 
two vafti mufcles have part of their origin from thefe 
ridges; and the long tendon of the triceps is fixed to the 
internal, by a part of the fafeia aponeurotica of the thigh. 
The lower end of the os femoris is larger than any other 
part of it, and is formed into a great protuberance on each 
fide, called its condyles ; between which a confiderable ca¬ 
vity is found, efpecially at the back-part, in which the 
crural veffels and nerves lie immerled in fat. The inter¬ 
nal condyle is longer than the external, which mull happen 
from the oblique polition of this bone, to give lefs obli¬ 
quity to the leg. Each of thefe proceffes feem to be divi¬ 
ded into its plain fmooth furface. The mark of divifion 
on the external is a notch, and on the internal a fmall 
protuberance. The fore-part of this divifion, on which 
the rotula moves, is formed like a pulley, the external fide 
of which is higheft. Behind, there are two oblong large 
heads, whole greateft extent is backwards, for the motion 
of the tibia ; and from the rough cavity between them, but 
near to the<bafe of the internal condyle, the ftrong liga¬ 
ment, commonly called the crofs one, has its rife. 
The thigh-bone being articulated above with the ace¬ 
tabulum of the offa innominata, which affords its round 
head a fecure and ektenfive play, can be moved to every 
fide; but is reftrained in its motion outwards by the high 
brims of the cavity, and by the round ligament; for other- 
wife the head of the bone would have been frequently 
thruft out at the breach of the brims on the inlide, which 
allows the thigh to move confiderably inwards. The body 
of this bone enjoys little or no rotatory motion, though the 
head moll commonly moves round its own axis; becaule 
the oblique progi'efs ot the necktind head from the bone 
is fuch, that the rotatory motion of the head can only 
bring the body of the bone forwards and backwards. Nor 
is the head, as in the arm, ever capable of being brought 
to a ftraight direftion with its body; fo far however, as 
the head can move within the cavity backwards and tor- 
wards, the bone may have a partial rotation. When the 
thigh-bone refills the adtions of its mufcles more than the 
trunk of the body can then do, as in Handing, thefe muf¬ 
cles have their effedl on the trunk, caufing it to bend for¬ 
ward, railing it up, inclining it to the one or the other fide, 
twilling it obliquely, &c. for which the rolling of the ace¬ 
tabula of the offa innominata on the round heads of the 
thigh-bones is well fitted. The nearnefs of the fmall neck 
to the round head of the thigh-bone, and its upper end 
being covered with very thick mufcles, make greater dif¬ 
ficulty in diftinguifhing between a luxation and Iradture 
here, than in any other part of the body. 
The leg is compofed of two bones, tibia and fbula, tho* 
it 
