ANATOMY. 
the teeth of a law ; and is inferted into the whole bafe of 
the fcapula, internally, between the infertion of the rhom¬ 
boid and the origin of the fubfcapularis mufcles, being 
folded about the two angles of the fcapula. It ferves to 
move the fcapula forwards ; and, when the fcapula is for¬ 
cibly raifed, to draw upwards the ribs. 
Muscles between the Ribs and within the Thorax. 
■.—Between the ribs, on each tide, there are eleven double 
rows of mufcles, which are named intercojlals. TJiefe de- 
culfate each other like the Itrokes of the letter X. i. fn- 
tercojlalcs externi, arife from the inferior acute edge of each 
fuperior rib, and run obliquely forwards, the whole length 
from the fpine to near the joining of the ribs with their 
cartilages; and are inferted into the upper obtufe edge 
of each inferior rib, as far back as the fpine, into which 
the pollerior portion is fixed. 2. Intercojiales interni , arife 
in the fame manner as the external : but they begin at the 
fternum, and run obliquely backwards, as far as the angle 
of the rib ; and are inferted in the fame manner as the ex¬ 
ternal. By means of thefe mufcles, the ribs are equally 
raifed upwards during infpiration. Their fibres being ob¬ 
lique, give them a greater power of bringing the ribs near 
each other, than could be performed by ftraight ones. But, 
by the obliquity of the fibres, they are almoft brought con¬ 
tiguous: and as the fixed points of the ribs are before and 
behind, if the external had been continued forwards to the 
flernum, and the infernal backwards to the fpine, it would 
have hindered their motion, which is greateft in the middle, 
though the obliquity of the ribs renders it lefs perceptible; 
and, inftead of railing the fibres fixed to the flernum and 
fpine, would have depreffed the ribs. The mufcles within 
the thorax are one pair, viz. triangularis or JlemocoJlalis, 
arifes from the cartilago enfiformis laterally, and from the 
edge of the lower half of the middle bone of the flernum, 
from whence its fibres afeend obliquely upwards and out¬ 
wards. It is inferted, generally by three triangular ter¬ 
minations, into the lower edge of the cartilages of the 
third, fourth, and fifth, ribs, near where thefe join with 
the ribs. Its ufe is to deprefs thefe cartilages, and the 
extremities of the ribs; and confequently to afiifl in con¬ 
trafling the cavity of the thorax. This mufcle often va¬ 
ries; and is fometimes inferted into the cartilage of the 
fecond rib; fometimes into the cartilage of the fixth rib. 
Muscles on the anterior part of the Neck.— 
Thefe confifl of one layer formed by four mufcles. 1. 
Longus colli, arifes from the bodies of the three vertebrae 
of the back laterally ; and from the tranfverfe procefs of 
the third, fourth, fifth, and fixth, vertebrae of the neck; 
and is inferted into the fore-part of the bodies of all the 
vertebrae of the neck. Its ufe is to bend the neck gradu¬ 
ally forwards, and to one fide. 2. Redus capitis internus 
major, arifes from the anterior points of the tranfverfe pre¬ 
cedes of the third, fourth, fifth, and fixth, vertebrae of 
the neck ; and is inferted into the cuneiform procefs of the 
os occipitis. Its ufe is to bend the head forwards. 3. Rec¬ 
tus capitis internus minor, arifes from the fore-part of the 
body of the firft vertebra of the neck; and is inferted 
near the root of the condyloid procefs of the os occipitis, 
under the former mufcle. Its ufe is to bend the head for¬ 
wards. 4. Redus capitis lateralis, arifes from the anterior 
part of the point of the tranfverfe procefs of the firft ver¬ 
tebra of the neck, and is inferted into the os occipitis, 
oppofite to the foramen ftylo-maftoideum of the temporal 
bone. Its ufe is to bend the head a little to one fide. 
Muscles on the posterior part of the Trunk.— 
Thefe may be divided into four layers, and a fingle pair. 
The firft layer confifts of two mufcles, which cover almoft 
the whole pofterior part of the trunk. 1. Trapezius feu 
cucu/aris, arifes from the middle of the os occipitis behind ; 
and from the rough curved line that extends from the pro¬ 
tuberance towards the maftoid procefs of the temporal 
bone; runs down the nape of the neck, and covers the 
fpinous procelfes of the fuperior vertebrae of the neck; but 
rifes from the fpinous proceftes of the two inferior, and 
from the fpinous procelfes of all the vertebrae of the back; 
Vol. I. No. 36. 
573 
adhering to its fellow the whole length of its origin. It 
is inferted into the pofterior half of the clavicle; into the' 
acromion, and into almoft all the fpine of the fcapula. It 
moves the fcapula according to the three different direc¬ 
tions of its fibres; for the upper defeending fibres draw it 
obliquely upwards, the middle tranfverfe ftraight fibres 
draw it directly backwards, and the inferior afeending fi¬ 
bres draw it obliquely downwards and backwards. Where' 
it is inseparably united to its fellow in the nape of the 
neck, it is named ligamentum nuchas or colli. 2. LatiJJimus 
dorji, arifes from the pofterior part of the fpine of the os 
ilium, from all the fpinous proceftes of the os facrum and 
vertebrae of the loins, and from the feven inferior ones of 
the vertebrae of the back; alfo from the extremities of 
the three or four inferior ribs, by as many diftinfit llips. 
T. ne inferior fibres afeend obliquely, and the fuperior run 
tranfverfely, over the inferior angle of the fcapula, to¬ 
wards the axilla, where they are all collected, twitted, and 
folded. It is inferted into the inner edge of the groove, 
for lodging the tendon of the long head of the biceps ; and 
ferves to pull the arm backwards and downwards, and to 
roll the os humeri. 
The fecond layer confifts of three pair, two on the back, 
and one on tne neck. On the back, 1. Serralus poflicus 
inferior, arifes in common with that of the latiflimus dorli, 
fiom the fpinal procelfes of the two inferior vertebrae of 
the back, and from the three fuperior vertebrae of the 
loins ; and is inferted into the lower edges of the four in¬ 
ferior ribs, at a little diftance from their cartilages; and 
mrves to deprefs the rihs into which it is inferted. 2. 
Rhomboideus. Hhis mufcle is divided into two portions: 
1. Rhomboideus major, arifes from the fpinous procelfes of 
tne five fuperior vertebrae of the back; and is inferted in¬ 
to all the balls of the fcapula below its fpine. This ferves 
to draw the fcapula obliquely upwards and direfilly in¬ 
wards. 2. Rhomboideus minor, arifes from the fpinous pro- 
celfes of the three inferior vertebrae of the neck ; and from 
the ligamentum nuchas ; and is inferted into the bafe of 
the fcapula, oppofite to its fpine. Its ufe is to affift the 
former. On the neck, 3. Splenius, arifes from the four 
fuperior fpinous procelfes of the vertebra: of the back, and 
horn the five inferior of the neck, and adheres firmly to 
the ligamentum nuchae. At the third vertebra; of the 
neck, the fplenii recede from each other, fo that part of 
the complcxus mufcle is feen. It is inferted into the five 
fuperior tranfverfe proceftes of the vertebra of the neck • 
and into the pofterior part of the maftoid procefs, and into 
the os occipitis. Its ufe is to bring the head and upper 
vertebra of the neck backwards laterally; and, when both 
act, to pull the head direfitly backwards. Albinus divides 
this mufcle into two; viz. that portion which arifes f rom 
the five inferior fpinous proceftes of the neck, and is ffi- 
ferted into the maftoid procefs and os occipitis, he calls 
fplenius capitis: and that portion which arifes from the 
third and fourth of the back, and is inferted into the 
five fuperior tranfverfe procelfes of the neck, is called by 
him fplenius colli. The fingle pair, ferratus fuperior poflicus 
arifes from the fpinous proceftes of the three laft vertebra 
ot the neck, and the two uppermoft of the back- is in 
ferted into the fecond, third, fourth, and fifth, ribs • and 
ferves to elevate the ribs, and dilate the thorax. ’ 
The third layer confifts of three pair on the back, and 
three on the neck. Thofe on the back are, 1. Spinalis 
dorf, arifes from the fpinous proceftes of the two upper 
moft vertebra of the loins, and the three inferior of the 
back; and. is inferted into the fpinous procelfes of the nine 
uppermoft vertebra of the back. Its ufe is to erefil and 
fix the vertebra, and to affift in raffing the fpine. 2 Lon 
gijfimus dorfi, arifes from the fide, and all the fpinous pro" 
cedes of the os facrum ; from the pofterior fpine of the os 
ilium; from all the fpinous procelfes; and from the roots 
of the tranfverfe procelfes of the vertebra of the loins It 
is inferted into all the tranfverfe proceftes of the vertebras 
of the back; and ferves to extend the vertebra, and re 
raife and keep the trunk of the body erect. 3’: kacr 0 . 
7 ^ lain half 
