A N A T 
From the roots of the metacarpal bones that fuftain the 
fore and middle fingers externally, and next each other; 
runs along the outlide of the middle \ finger; and, being 
confpicuous on both fides of the hand, is infected into the 
.outlide of the tendinous expanfion from the ex ten for digi- 
■ torqm communis, which covers the pofterior part of the 
middle finger. It ferves to extend, and to draw the mid¬ 
dle finger inwards. 2. Pujierior medii, ariles from the roots 
' of the metacarpal bones, next to each other, that fuftain 
the middle and ring fingers; and is inferted into the inlide 
of the tendinous expanfion from the extenfor digitorum 
■ communis, which runs along the pofterior part of the 
middle finger. Its ufe is to extend and draw the middle- 
finger outwards. 3. Pofterior annularis, arifes from the 
' roots of the metacarpal bones that fuftain the ring and lit¬ 
tle fingers next each other, and is inferted into the infide 
of the tendinous expanfion of the extenfor digitorum com¬ 
munis, which runs along the pofterior part of the ring- 
finger. Its ufe is to extend and draw the ring-finge,r inwards. 
Muscles of the Inferior Extremities. —Thefe 
may be divided into the mufcles fituated on the outfide of 
the pelvis, on the thigh, on the leg, and on the foot. The 
mufcles on the outfide of the pelvis, which are called muf¬ 
cles of the thigh, are compofed of one layer before, and three 
layers behind. The layer before confifts of five mufcles: 
1. PJ'oas magnus, 2. I/iacus internus ; both which are already 
deferibed in page 572. 3. PcElinalis, arifes from the upper 
and anterior part of the os pubis or peftinis, and is infert¬ 
ed into the anterior and upper part of the linea afpera of 
the os femoris, a little below the trochanter minor. Its 
ufe is to bring the thigh upwards and inwards, and to give 
it a degree of rotation outwards. 4. Tricepsaddubtorfemo¬ 
ris-, under which application are comprehended three dil- 
tinct mufcles : i. AdduElor longus femoris, arifes fronr the 
upper and inferior part of the os pubis, and ligament of 
its fynchondrolis, on the inner fide of the peftinalis; and 
is inferted near the middle of the pofterior part of the li¬ 
nea afpera, being continued for fome way down. ii. Ad- 
duElor brevis femoris, arifes from the os pubis near its joining 
with the oppofite os pubis below and behind the former; 
and is inferted into the inner and upper part of the linea 
afpera, from a little below the trochanter minor, to the 
beginning of the infertion of the addudtor longus. iii. Ad¬ 
duElor magnus femoris, arifes a little lower down than the 
former, near the fymphafis of the ofla pubis; and is in¬ 
ferted into almoft the whole length of the linea afpera; 
into a ridge above the internal condyle of the os femoris; 
and into the upper part of that condyle, a little above 
which the femoral artery takes a fpinal turn towards tire 
ham, paffing between this mufcle and the bone. The ufe 
, of thefe three mufcles or triceps is, to bring the thigh in¬ 
wards and upwards, according to the different directions 
of their fibres ; and, in fome degree, to roll the thigh out¬ 
wards. 5 .Obturator externus, arifes from the lower fore¬ 
part of the os pubis, and fore-part of the inner crus of 
the ifehium, and furrounds the foramen thyroideum. It 
is inferted into the cavity at the inner and back part of the 
root of the trochanter major, adhering in its courfe to 
the capfular ligament of the thigh-bone; and is ufed to 
roll the thigh-bone obliquely outwards, and to prevent the 
capfular ligament from being pinched. 
The mufcles behind are: Firft layer, gluteus maximus, 
arifes from the pofterior part of the fpine of the os ilium ; 
from the w,hole external fide of the os facrum ; from the 
pofterior facro-ifchiatic ligament, over which part of the 
inferior edge of this mufcle hangs in a folded manner; and 
from the os coccygis. All the fiefhy fibres run obliquely 
forwards, and a little downwards, to form a thick broad 
mufcle, which is divided into a number of ftrong fafciculi. 
It is inferted into the upper and outer part of the linea. 
afpera, which is continued from the trochanter major; 
and its ufe is to extend the thigh, by pulling it directly 
backwards, and a little outwards. 
The fecond layer confifts of gluteus medius, which arifes 
from the anterior fuperior fpinous procefs of the os ilium, 
Vol. I. No. 37. 
O M Y. 577 
and from all the outer edge of the fpine of the ilium, ex¬ 
cept its pofterior part, where it ariles from the dorfum of 
that bone. It is inferted into the outer and pofterior part 
of the trochanter major; and its ufe is to draw tire thigh¬ 
bone Outwards, and a little backwards; and to roll the 
thigh-bone outwards, efpecially when it is bended. 
The third layer confifts of four mufcles, viz. 1. Gluteus 
minimus, arifes from a ridge that is continued from thefii- 
perior anterior fpinou.s pi ocefs of the os ilium, and from 
the middle of the dorfum of that bone as far back as its 
great niche. It is inferted into the fore and upper part of 
the trochanter major; and ferves to aflift the former in 
pulling the thigh'outwards and backwards, and in rolling 
it. 2. Pyriformis , ariles within the pelvis, by three tendi¬ 
nous and fleftiy origins, from the fecond, third, and fourth, 
pieces of the os facrum; from thence, growing gradually 
narrower, it paftes out of the pelvis along with, the pofte¬ 
rior crural nerve, below the niche in the pofterior part of 
the os ilium, where it receives a few fleftiy fibres. It is 
inferted into the upper part of the cavity at the inner fide 
of-the root of the trochdnter major. Its ufe is to move 
the thigh a little upwards, and roll it outwards. 3. Gemi¬ 
ni, ariles by two diftindt origins; the fuperior from the 
fpinous procefs, and the inferior from the tuberolity of 
the os ifehium; alfo, from the pofterior facro-ifchiatic li¬ 
gament. It is inferted into the cavity at the inner fide of 
the root of the trochanter major, on each fide of the ten¬ 
don of the obturator internus; and its ule is to roll the 
thigh outwards, and to preferve the tendon of the obtu¬ 
rator internus from being hurt by the hardnefs of that 
part of the ifehium over w'hich it paftes; alfo, to hinder 
it from ftarting out of its piace, while the mufcle is in ac¬ 
tion. 4. Quadratus femoris, arifes from the outlide of the 
tuberolity of the os ifehium; and, running tranfverfely, 
is inferted into a rough ridge, continued from the root of 
the large trochanter to the root of the fmall one. Its ufe 
is to roll the thigh outwards. 
Muscles on the Thigh. —Thefe are called mufcles of 
the leg-, and confift of one on the outfide, two on the infide , 
four before, and four behind. On the outlide is, tenfor va¬ 
gina femoris. It arifes from the external part of the an¬ 
terior fuperior fpinous procefs of the os ilium; and is in¬ 
ferted a little below the trochanter major, into the inner 
fide of the membranous fafeia which covers the outfide 
of the thigh. Itftretches the membranousfafeia, allifts in the 
abdudtion of the thigh, and helps its rotation inwards. 
On the infide are: 1. Sartorius, arifes from the anterior 
fuperior fpinous procefs of the os ilium, runs down upon 
the reftus, and, going obliquely inwards, it paftes over 
the vaftus internus, and about the middle of the os femo¬ 
ris, over part of the triceps, it runs down farther between 
the tendon of the abdudtor magnus and that of the gracilis 
mufcle. It is inferted into the inner fide of the tibia, near 
the inferior part of its tubercle; and ferves to bend the 
leg obliquely inwards, or to bring one legacrofs the other. 
2. Gracilis, arifes from the os pubis near the fymphyfis of 
thefe two bones. It defeends by the infide of the thigh, and 
is inferted into the tibia under the fartorius; which it allifts. 
Thofe before are: 1. ReElus, arifes from the inferior an¬ 
terior fpinous procefs of the os ilium, and from the dor- 
fum of the ilium, a little above the acetabulum; runs 
down over the anterior part of the cervix of the os femo¬ 
ris, the fibres not being ftraight, but running down like the 
plumage of a feather obliquely’ outwards and inwards, 
from a tendon in the middle ; and is inferted into the up¬ 
per part of the patella, from which a thin tendon runs 
down, on the fore-part of this bone, to terminate in a 
thick ftrong ligament, which is fent off from the inferior 
part of the patella, and inferted into the tubercle of the 
tibia. Its ufe is to extend the leg in a powerful manner, 
by the.intervention of the patella, like a pulley. 2. Vafus 
externus, arifes from the root of the trochanter major, and 
upper part of the linea afpera, its origin being contained 
from near the infertion of the gluteus minimus, the wholo 
length, of the linea afpera, by flelhy fibres which run 
7 Ii obliquely 
