578 A N A 1 
obliquely forwards to a middle tendon, where they termi¬ 
nate. It is inferted into a large lliare of the upper part of 
the patella; and part of it ends in an aponeurofis, which 
is continued down to the leg, and in its paffage is firmly 
fixed to the head of the tibia. Its life is to extend the 
leg. 3. I'aflus internus, arifes from between the fore-part 
of the os femoris and root of the trochanter minor, and 
from almoft all the infide of the linea afpera, by fibres 
running obliquely forwards and downwards. It is infert¬ 
ed into the upper and infide of the patella, continuing 
flefiiy lower than the vafitts externus. Part of it likewife 
ends in an aponeurofis continued down to the leg, and fixed 
in its padage to the upper part of the tibia. The ufe of 
this alfo is to extend the leg. 4. Cruralis, arifes from be¬ 
tween the two trochanters of the os femoris, but nearer 
the minor, and firmly adhering to mod of the fore-part 
of the os femoris, and connected to both vafti mufcles. 
It is inferted into the upper part of the patella, behind the 
rectus; and alfo affifts in the extenfionof the leg. Thefe 
four mufcles before, being inferted into the patella, have 
the fame effedt upon the leg as if they were immediately 
inferted into it, by means of the ftrong tendon, or rather 
ligament, which is fent oft' from the inferior part of the 
patella to the tibia. 
Thofe behind are : j. Semitendinofus, arifes from the pof- 
terior part of the tuberofity of the os ifchium; and is in¬ 
ferted into the infide of the ridge of the tibia, a little 
below its tubercle. Its ufe is to bend the leg backwards 
and a little inwards. 2. Setnimembranofus, arifes from the 
upper and poflericr part of the tuberofity of the os ifchi¬ 
um, and is inferted into the inner and back part of the 
head of the tibia. Its ufe is to bend the leg, and bring 
it diredtly backwards. Thefe two laft mufcles form what 
is called the inner hamjiring. 3. BicepsJlcxor cruris, arifes 
by two diftinct heads. The firft, called longus, arifes, in 
common with the femitendinofus, from the upper and 
poflericr part of the tuberofity of the os ifchium. The 
fecond, called brevis, arifes from the linea afpera, a little 
below the termination of the gluteus maximus ; and is 
inferted into the upper part of the head of the fibula. Its 
ule is to bend the leg. This is called the outer hamjiring ; 
and between it and the inner the nervous popliteus andar- 
teria vena poplitea are lituated. 4. Popliteus, arifes from 
tb.e lower and back part of the external condyle of the os 
femoris; then runs over the ligament that involves the 
joint, firmly adhering to it, and part of the femilunar car¬ 
tilage. It is inferted into a ridge at the upper and inter¬ 
nal edge of the tibia, a little below its head; and its ufe 
is to aftift in bending the leg, and to prevent the cap- 
fular ligament from being pinched. After the leg is bent, 
this mufcle alfo ferves to roll it inwards. 
Muscles of the Leg. —Thefe are called mufcles of the 
foot ; and may be divided into two claffes, viz. extenjors and 
Jlexors of the foot ; and common extenfor s and flexors of the 
toes. Firft clafs: The extenfors are, 1. Gaflrocnanius ex¬ 
ternus, feu gemellus, which arifes by two diftinct heads. The 
firft head arifes from the upper and back part of the in¬ 
ternal condyle of the os femoris, and from that bone, a 
little above its condyle. The fecond arifes from the up¬ 
per and back part of the external condyle of the os femo¬ 
ris. 2. So/cus, feu gaflrocnemius internus, arifes by tw r o ori¬ 
gins. The firft is from the upper and back part of the 
head of the fibula ; the fecond begins from the pofterior 
and upper part of the middle of the tibia. The flefh of 
this mufcle, covered by the tendon of the gemellus, runs 
down near as far as the - extremity of the tibia; a little 
above which the tendons of both gaftrocnemii unite, and 
form a. ftrong round cord, which is called tendo Achillis. 
It is inferted into the upper and pofterior part of the os 
calcis; by the projection of which the tendo Achillis is at 
a confiderable diftance from the tibia. Its ufe is to extend 
the foot, by bringing it backwards and downwards. 3. 
P/antaris, arifes from the upper and back part of tb.e root 
of the external condyle of the os femoris, near the infe¬ 
rior extremity of that bone, adhering to the ligament that 
" O M Y. 
involves the joint in its defeent. It is inferted into the in¬ 
fide of the pofterior part of the os calcis, below the tendo 
Achillis; and its ufe is to aftift the former, and to pull the 
capfular ligament of the knee from between the bones. 
It feems likewife to aftift in rolling the foot inwards. 
The flexors confift of four mufcles: two belong to the ti¬ 
bia, and tw'o to the fibula. 1. Tibialis anticus, arifes from 
the middle of that procefs of the tibia, to which the fibu¬ 
la ri connected above; then it runs down flelhy on the 
outlide of the tibia; from which, and the upper-part of 
the interoffeus ligament, it receives a number of diftinft 
flelhy fibres. It is inferted into the infide of the os cunei- 
forme internum, and pofterior end of the metatarfal bone 
that fuftains the great toe; and ferves to bend the foot, by 
drawing it upwards, and, at the fame time, to turn the 
toes inwards. 2. Tibialis prflicus, arifes from the fore and 
upper part of the tibia, juft under the procefs which joins 
it to the fibula; then, palling through a perforation in the 
upper part of the interofleus ligament, it continues its 
origin from the back-part of the fibula. It is inferted in¬ 
to the upper and inner part of the os naviculare, and 
gives fome tendinous filaments to the os calcis, os cuboides, 
and to the root of the metatarfal bone that fuftains the 
middle toe. Its ufe is to extend the foot, and to turn the 
toes inwards. 3. Pcroneus longus, arifes from the fore-part 
of the head of the perone, or fibula, the fibres running 
ftraight down; alfo from the upper and external part of 
the fibula, where it begins to rife into a round edge; as 
alfo, from the hollow between that and its anterior edge, 
as far down as to reach within a hand's breadth of the an¬ 
kle, by a number of flelhy fibres, which run outwards 
towards a tendon, that fends off a long round one, which 
palles through a channel at the outer ankle, in the back- 
part of the inferior extremity of the fibula; then,, being 
refledted to the linuofity of the os calcis, it runs along a 
groove in the os cuboides, above the mufcles in the folc 
ol the foot. It is inferted into the outlide of the root of 
the metatarfal bone that fuftains the great toe, and by fome 
tendinous fibres in the os cuneiforme internum. Its ufe is 
to move and extend the foot outwards. 4. Peroneus brevis, 
arifes from above the middle of the external part of the 
fibula; from the outer fide of the anterior fpine of this; 
bone; as alfo, from its round edge externally, the fibres- 
running obliquely outwards towards a tendon on its ex¬ 
ternal fide. It is inferted into the root and external part 
of the metatarfal bone that fuftains the little toe; and 
ferves to aflift the former. 
Second clafs: The common extenfors confift of two 
mufcles. 1. Extenfor longus digitorum pedis, arifes from the 
upper and outer part of the head of the tibia, and from 
the head of the fibula, and from the interoffeous ligament; 
alfo from the tendinous fafeia, which covers the upper 
and outlide of the leg by a number of flelhy fibres; and 
from the anterior fpine of the fibula, almofl; its whole 
length, where it is infeparable from the peroneus tertius. It 
is inferted into the root of the firft joint of each of the 
four fmall toes; and is expanded over t!ie upper fide of 
the toes, as far as the root of the laft joint; and ferves to 
extend all the joints of the fourfmall toes. A portion of 
this mufcle, which arifes from the middle of the fibula, 
continues down to its inferior extremity, and fends its fiefhy 
fibres forwards to a tendon, which palles under the annu¬ 
lar ligament, and is inferted into the root of the metatar¬ 
fal bone that fuftains the little toe. It is called by Albi¬ 
nos peroneus tertius, and by others the nonus vefalii. It 
ferves to aftift in bending the foot. 2. Extenfor brevis digi¬ 
torum pedis , arifes from the fore and upper part of the os 
calcis, and is inferted into the tendinous expanfion front 
the extenfor longus, which covers the fmall toes, except 
the little one ; alfo into the tendinous expanfion from the 
extenfor pollicis that covers the upper part of the great 
toe. Its ufe is to extend the toes. 
The flexors may be reckoned three. 1. Flexor brevis dS- 
gitorum pedis, fublimis perforatus, arifes from the inferior 
and pofterior part of a protuberance of the os calcis, be- 
3 tween 
