f- The most internal or deep-seated layer of muscles between the os
hyoides and lower jaw, consists of two on each side, of the genio-
hyo-glossus nearest the chin, and of this muscle which is situated
nearer the angle of the jaw than the genio-hyo-glossus. The stylo-
glossus and hyo-glossus generally unite before they are inserted into
the tongue.



30 DESCRIPTION OF

Basio cerato-chondro-glossus, Albinus,
Cerato-glossuS) Douglas .

2. LINGUALIS, *

Arises from the root of the tongue laterally ;
runs forwards between the hyo-glossus and genio-
glossus, to be

Inserted into the tip of the tongue, along with
part of the stylo-glossus.

Use. To contract the substance of the tongue,

and bring it backwards.

.



CHAP. X.

MUSCLES SITUATED BETWEEN THE OS
HYOIDES AND TRUNK, f

THESE may be divided into two layers.
The first layer consists of two muscles.

1. STERNO-HYOIDEUS,

Arises, thin and fleshy, from the cartilaginous

* The tongue is formed by the assemblage of four muscles upon
each side. Three of these come from the parts in the vicinity, as the
hyoid bone, the chin, and styloid process, and are calculated to im-
part great mobility as well as substance to that organ. The fourth,
or lingualis, is properly the muscle of the tongue, as it commences
and terminates there, and forms a large portion of its substance. 1 1
should be exposed upon the lower surface of the tongue.

f In the forepart of the neck a number of prominences are si*
tuated, which are often referred to as .points of origin and insertion



THE MUSCLES. 31

extremity of the first rib, the upper and inner part
of the sternum, and from the clavicle where it
joins with the sternum.

Inserted into the base of the os hyoides.

Use. To pull the os hyoides downwards.



of muscles, and are likewise the land-marks in guiding the surgeon
through some delicate operations. The student should, therefore,
accustom himself to recognise them familiarly in the undissected,
as well as the dissected state of parts. The uppermost is formed by
the os hyoides, and is situated behind, and nearly upon a level with
the base of the lower jaw, when the crown of the head is parallel
with the horizon. The next is formed by the thyroid cartilage, and
is always more conspicuous than the rest. The cricoid cartilage
forms the third, and is nearly in contact with the lower edge of the
thyroid cartilage ; while the fourth appears to be rather a gentle
swelling of the sides, than an eminence on the anterior of the neck.
This is attributable to the form of the thyroid gland, which is thin
and narrow where it lies before the trachea, but bulges out consi-
derably upon each side of the neck.

Between the anterior margins of the scernotcleido-mastodei mus-
cles, the sterno-hyoid, the sterno-thyroid, and the anterior portion
of the omo-hyoid muscles are situated. The sterno-hyoid will be
found upon the fore part of the trachea, immediately under the pla-
tysma myoides. The sterno-thyroid is broader than the sterno-
hyoid, and lies under it. The anterior portion of the omo-hyoid, is
placed on the outer edge of the sterno-hyoid. About two inches
and a half above the clavicle the omo-hyoid crosses the neck between
the sterno-cleido-mastoid muscle and the great blood vessels and
nerves situated there, and is covered at the shoulder by the tra-
pezius.

The other two small muscles which are situated close upon the
larynx anteriorly, viz. the thyreo-hyoideus and crico-thyroideus,
may either be dissected with the long muscles, or may be left till the
other muscles of the larynx are displayed. While dissecting this
part of the neck, the student should particularly study the following
points. First. The relative situation of the thyroid gland ; to the
muscles which cover it ; to the parts which it likewise covers, and
the probable effects of an enlargement of that gland. Secondly.
The comparative merits of opening the windpipe, below the thyroid
glandjand between the thyroid and cricoid cartilages. Thirdly. The
depth and relations of the carotid artery, above and below the omo-
hyoid muscle.



32 DESCRIPTION OF

2. OMO-HYOIDEUS,

Arises, broad, thin and fleshy, from the superior
costa of the scapula, near the semilunar nitch,
and from the ligament that runs across it ; thence
ascending obliquely, it becomes tendinous below
the sterno-cleido-mastoid muscle; and, growing
fleshy again, is

Inserted into the base of the os hyoides between
its cornu and the insertion of the sterno-hyoideus.

Use. To pull the os 'hyoides obliquely down-
wards.

Coraco hyoideits, Albinus and Douglas.

The second layer consists of three muscles.

1. STERNO-THYROIDEUS,

Arises, fleshy, from the whole edge of the up-
permost bone of the sternum internally, opposite
to the cartilage of the first rib, from which it re-
ceives a small part of its origin.

Inserted into the surface of the rough line at the
external part of the inferior edge of the thyroid
cartilage.

Use. To draw the larynx downwards.

2. THYREO-HYOIDEUS,

Inserted into part of the basis, and almost all
the cornu of the os hyoides.

Arises from the rough line, opposite to the
former.

Use. To pull the os hyoides downwards, or the
thyroid cartilage upwards.



THE MUSCLES. 33

Thyro-hyoideus, vel Hyo-thyroideus, Winslow,

3. CRICO-THYROIDEUS,

Arises from the side and fore part of the cricoid
cartilage, running obliquely upwards.

Inserted by two portions ; the first, into the
lower part of the thyroid cartilage; the second,
into its inferior ^cornu.

Use. To pull forwards and depress the thy-
roid, or to elevate and draw backwards the cricoid
cartilage.



CHAR XL

MUSCLES SITUATED BETWEEN THE LOWER
JAW AND OS HYOIDES LATERALLY.

THEY are five in number. Three proceed from
the styloid process of the temporal bone, from
which they have half their names; and two from
the pterygoid process of the sphenoid bone.

The three from the styloid process are, *

1. STYLO-GLOSSUS,

Arises, tendinous and fleshy, from the styloid



* Besides .these three muscles, two ligaments will be found to

arise from the same point, one of. which is inserted into the os

hyoides, the other into the angle of the lower jaw. Of the three

. muscles, the stylo-hyoideus is the most superficial, the stylo-glossus

i the next, and the stylo-pharyngeus the most deep-seated.

c 2



34 DESCRIPTION OF

process; and from a ligament that connects that
process to the angle of the lower jaw.

Inserted into the root of the tongue, runs along
its side, and is insensibly lost near its tip.

Use. To draw the tongue laterally and back-
wards.

2. STYLO-HYOIDEUS,

Arises, by a round tendon, from the middle and
inferior part of the styloid process

Inserted into the os hyoides at the junction of
the base and cornu.

Use. To pull the os hyoides to one side, and a
little upwards.

N. B. Its fleshy belly is generally perforated
by the tendon of the digastric muscle, on one or
both sides. There is often another accompanying
it, called stylo-hyoideus alter ; and has the same
origin, insertion, and use.

3. STYLO-PHARYNGEUS,

Arises, fleshy, from the root of the styloid pra-
cess.

Inserted into the side of the pharynx and back
part of the thyroid cartilage.

Use. To dilate and raise the pharynx and thy-
roid cartilage upwards.

The two from the pterygoid process are, *

* The muscles which are situated about the velum and pharynx
can with difficulty be dissected, unless a perpendicular section be
made of the cranium. If the section, pass immediately before the



THE MUSCLES. 35

1. CIRCUMFLEXUS, OR TENSOR PALATI, *

Arises from the spinous process of the sphenoid
bone, behind the foramen ovale, which transmits
the third branch of the fifth pair of nerves ; from
the Eustachian tube, not far from its osseous part :
it then runs down along the pterygoideus interims,
passes over the hook of the internal plate of the
pterygoid process by a round tendon, which soon
spreads into a broad membrane.

Inserted into the velum pendulum palati, and
the semilunar edge of the os palati, and extends
as far as the suture which joins the two bones.
Generally some of its posterior fibres join with
the constrictor pharyngis superior, and the palato-
pharyngeus.

Use. To stretch the velum, to draw it down-
wards, and to a side towards the hook. It has
little effect upon the tube, being chiefly connected
to its osseous part.

Circumflexus palati^ Albinus.

Spheno-salpingo-staphilinus, seu Staphilinus ex
ternus, Winslow.

Musculus iubtc novuSy Valsalva^ vel Palato-sal-
pingeuS) Douglas.



condyles of the occipital bone, it will lead between the longi colli
muscles and the back of the pharynx. By this dissection one can
obtain an excellent posterior view of the muscles of the velum, of the
muscles of the pharynx, and when these are removed, of the muscles
of the larynx.

* The fleshy belly of this muscle, where it lies between the laminae
of the pterygoid process, should be exposed first, and the muscle
then traced over the hook into the velum.



36 DESCRIPTION OF

2. LEVATOR PALATI, *

Arises, tendinous and fleshy, from the extremity
of the pars petrosa of the temporal bone, where it
is perforated by the Eustachian tube, and also
from the membranous part of the same tube.

Inserted into the whole length of the velum pen-
dulum palati, as far as the root of the uvula, and
unites with its fellow.

Use. To draw the velum upwards and back-
wards, so as to shut the passage from the fauces
into the mouth and nose.

Levator palati mollis, Albinus.

Petro salpingo-slaphilinus, vel Salpingo staphi-
linus interims, Winslow.

Salpingo-staphilinus, Valsalva. Pterygo staphi-
linus externus, vu/go, Douglas,

Spheno staphilinus, Cowper.

Previous to the description of the muscles si-
tuated about the passage into the throat, it will be
necessary to mention the .principal parts to which
they are connected.

Upon looking into any person's mouth, when
wide opened, we see a soft curtain hanging from
the palate-bones, named velum pendulum palali.
In the middle of which, we likewise observe a
papilla projecting from the velum, named uvula,
or pap of the throat. From each side of the uvula,

* The levator palati is separated from the internal side of the
tensor palati by a considerable quantity of cellular substance, and
its anterior surface is covered at its lower part by the palato-pha-
ryngeus.



TtiE MUSCLES. 37

at its root, two arches, or columns, are sent down,
the anterior to the root of the tongue, the poste-
rior to the pharynx. Between these arches, on
each side, the cellular glands called amygdala, or
almonds of the ears*, are situated.

The common opening between the anterior arch
may be named fauces, or top of the throat, from
which there are six passages, viz. two upwards,
being one to each nostril ; two at the sides, or one
to each ear, called the Eustachian tubes ; two
downwards ; the anterior is the passage through
the glottis and larynx, into the trachea, which ter-
minates in the lungs ; the posterior is the largest,
named pharynx, or top of the oesophagus, which
leads to the stomach.



CHAP. XII.

MUSCLES SITUATED ABOUT THE ENTRY TO
THE FAUCES.



THERE are two on each side, and a single one
in the middle.

The two on each side are, f

1. CONSTRICTOR ISTHMI FAUCIUM,

Arises, by a slender beginning, from the side of
the tongue, near its root; from thence running

* Tonsils,
t The two arches of the velum, which can be seen by looking into



38 DESCRIPTION OF

upwards, within the anterior arch, before the
amygdala, it is

Inserted into the middle of the velum pendu-
lum palati, at the root of the uvula anteriorly,
being connected with its fellow, and with the be-
ginning of the palato-pharyngeus.

Use. Draws the velum towards the root of the
tongue, which it raises at the same time, and,
with its fellow, contracts the passage between the
two arches, by which it shuts the opening into the
fauces.

Glosso-staphilinus, Winslow and Douglas.

2. PALATO-PHARYNGEUS,

Arises, by a broad beginning, from the middle
of the velum pendulum palati, at the root of the
uvula posteriorly, from the tendinous expansion
of the circumflexus palati, and from the carti-
laginous extremity of the Eustachian tube. The
fibres are collected within the posterior arch be-
hind the amygdala, and run backwards to the top
and lateral part of the pharynx, where the fibres
are scattered, and mix with those of the stylo-
pharyngeus.

Inserted into the edge of the upper and back
part of the thyroid cartilage; some of its fibres
being lost between the membrane of the pharynx
and the two inferior constrictors.



the mouth, and between which the tonsils are situated, are formed
by the two following muscles. The anterior arch by the constrictor
isthmi faucium, and the posterior by the palato-pharyngeus. The
dissection principally consists in removing the mucus membrane
which covers them.



THE MUSCLES. 39

Use. Draws the uvula and velum downwards
and backwards ; and at the same time pulls the
thyroid cartilage and pharynx upwards, and
shortens it ; with the constrictor superior and
tongue, it assists in shutting the passage into the
nostrils ; in swallowing, it thrusts the food from
the fauces into the pharynx, and dilates the mouth
of the Eustachian tube.

Thyro-staphilinitS) Douglas.

Thyro-pharyngo-staphilinus, Winslow.

The one in the middle is the

AZYGOS UVUL^j *



^ Arises, fleshy, from the extremity of the suture
which joins the palate-bones, runs down the whole
length of the velum and uvula, resembling a small
earth worm, and adhering to the tendons of the
circumflex!.

Inserted into the tip of the uvula.

Use. Raises the uvula upwards and forwards,
and shortens it.

Palato-staphilmus, Douglas.

Staphtlinus, or Epistaphilinus, Winslow.



* The two preceding muscles must be dissected from before, but
as this muscle runs along the middle and back of the velum, it can
only be dissected from behind. By removing the membrane from
the posterior surface of the velum the muscle becomes exposed.



40 DESCRIPTION OF



CHAP. XIII.

MUSCLES SITUATED ON THE POSTERIOR
PART OF THE PHARYNX. *

OF these there are three pair.

1. CONSTRICTOR PHARYNGIS INFERIOR,

Arises from the side of the thyroid cartilage,
near the attachment of the sterno-hyoideus and
thyreo-hyoideus muscles; and from the cricoid car-
tilage, near the crico-thyroideus. This muscle is
the largest of the three,, and is

Inserted into the white line, where it joins with
its fellow; the superior fibres running obliquely
upwards, co-vefing nearly one-half of the middle
constrictor, and terminating in a point ; the inferi-
or fibres run more transversely, and cover the be-
ginning of the esophagus.

Use. To compress that part of the pharynx
which it covers, and to raise it with the larynx a
little upwards.

Thyrorpharyngeus, Crico-pharyngeus, Douglas.

-* -The pharynx, is that bag or tube which leads from the mouth to
the esophagus, or rather is the commencement of the esophagus itself.
It extends from the isthmus of the fauces, to the inferior margin of
the thyroid cartilage, when it becomes suddenly contracted, and re-
ceives the name of esophagus. The three constrictors form a stiong
wall, posteriorly, for the pharynx, and the one muscle will be found
to overlap the other ; the inferior to overlap the middle, and the
middle the superior. They are connected by loose cellular substance
to the rectus capitus anticus and longus colli. As foreign bodies are
more apt to lodge at the junction of the pharynx and esophagus,
than at any other part of the tube, the student should attend to the
relative connections of that part with particular care.



THE MUSCLES.



2. CONSTRICTOR PHARYNGIS MEDIUS,

Arises from the appendix of the os hyoides, from
the cornu of that bone, and from the ligament
which connects it to the thyroid cartilage; the
fibres of the superior part running obliquely up-
wards, and covering a considerable part of the su-
perior constrictor, terminate in a point

Inserted into the middle of the cuneiform process
of the os occipitis, before the foramen magnum,
and joined to its fellow at a white line in the mid-
dle back part of the pharynx. The fibres at the
middle part run more transversely than those above
or below.

Use. To compress that part of the pharynx
which it covers, and to draw it and the os hyoides
upwards.

Hyo-pharyngeuS) Syndesmo-pharyngeus, Douglas.

3. CONSTRICTOR PHARYNGIS SUPERIOR,

Arises, above, from the cuneiform process of the
os occipitis, before the foramen magnum, near the
holes where the ninth pair of nerves passes out ;
lower down, from the pterygoid process of the
sphenoid bone; from the upper and under jaw,
near the roots of the last dentes inolares ; and be-
tween the jaws, it is continued with the buccinator
muscle, and with some fibres from the root of the
tongue and from the palate.

Inserted into a white line in the middle of the
middle of the pharynx, where it joins with its fel-
low, and is covered by the constrictor medius.



42 DESCRIPTION OF

Use. To compress the upper part of the pha-
rynx, and draw it forwards and upwards.
Cephalo-phari/Hgeus, Pterygo-phari/ngeus,
Mylo-pharyngeuS) Glosso-pharyngeus, Douglas.



CHAP. XIV.
MUSCLES SITUATED ABOUT THE GLOTTIS.*

THEY consist generally of four pair of small
muscles, and a single one.

* Before the student can understand the muscles of the larynx,
he must be acquainted, in some degree, with the structure of the la-
rynx itself. At all events, he must know the cartilages of which it
is composed. They are five in number, the thyroid, the cricoid, the
two arytenoid, and the epiglottis. The thyroid and cricoid are larger
than the others, and can be distinctly recognised through the skin
upon the anterior of the neck. They form the prominence which is
well known under the name of the pomum adami. The thyroid
forms the greater part of that prominence, and has a striking resem-
blance to the flood-gates of a canal. The cricoid is a cartilaginous
ring, deep, behind where it forms a support for the arytenoid carti-
lages, and narrow, before where it is connected to the lower margin
of the thyroid. The arytenoid cartilages, are two small pyramidal
bodies, which rise up from the margin of the cricoid cartilage, behind
the walls of the thyroid ; and when dissected have a slight resem-
blance to the spout of a ewer. The most important muscles of the
larynx are attached to these. The entrance to the windpipe is formed
between them and the thyroid. It is a longitudinal chink which ex-
tends from before, backwards, and is called glottis, or rima glottidis.
The epiglottis is a fibre-cartilaginous substance, resembling the ar-
tichoke leaf. It is more elastic than any of the other cartilages, and
being connected with the root of the tongue, has generally been con-
ceived useful for covering the glottis, when a morsel of food passed
into the esophagus. Magendie, however, by a number of convincing
experiments, has proved it to be an organ of voice, and not of deglu-
tition.



THE MUSCLES. 43

1. CRICO-ARYTJENOIDEUS POSTICUS,

Arises, fleshy, from the back part of the cricoid
cartilage, and is

Inserted into the posterior part of the base of the
arytenoid cartilage.

Use* To open the rima glottidis a little ; and,
by pulling back the arytenoid cartilage, to stretch
the ligament so as to make it tense.

2. CRICO-ARYT^ENOJDEUS LATERALIS,

Arises, fleshy, from the cricoid cartilage, later-
ally, where it is covered by part of the thyroid,
and is

Inserted into the side of the base of the arytenoid
cartilage near the former.

Use. To open the rima glottidis, by pulling the
ligaments from each other.

3. THYREO-ARYT^NOIDEUS,

Arises from the under and back part of the mid-
dle of the thyroid cartilage ; and, running back-
wards and a little upwards, along the side of the
glottis, is

Inserted into the arytenoid cartilage, higher up
and farther forwards than the crico-arytsenoideus
lateralis.

Use. To pull the arytenoid cartilage forwards,
nearer to the middle of the thyroid, and conse-
quently to shorten and relax the ligament of the
larynx or glottis vera.



44 DESCRIPTION OF

4. ARYT^NOIDEUS OBLIQUUS,

Arises from the base of one arytenoid cartilage:
and, crossing its fellow, is

Inserted near the tip of the other arytenoid car-
tilage.

Use. When both act, they pull the arytenoid
cartilages towards each other.

N. B. Very often one of these is wanting.

Aryttenoideus minor, Douglas.

The single .muscle is the

ARYTyENOlDEUS TRANSVERSUS,

Arises from the side of the one arytenoid carti-
lage, from near its articulation with the cricoid to
near its tip. The fibres run straight across ; and
are

Inserted, in the same manner, into the other
arytenoid cartilage.

Use. To shut the rima glottidis, by bringing
these two cartilages, with the ligaments, nearer one
another.

Aryt&noideus major, Douglas.

Besides these there are a few disgregated mus-
cular fibres on each side ; which, from their gene-
ral direction, are named,

1. THYREO-EPIGLOTTIDEUS,

Arises, by a few pale disgregated fibres, from
the thyroid cartilage; and is
Jnserted into the epiglottis laterally.



THE MUSCLES. 45

Use. To draw the epiglottis obliquely down-
wards, or, when both act, directly downwards;
and, at the same time, it expands that soft cartilage.

2. ARYTJENO-EPIGLotTIDEUS,

Arises, by a number of small fibres, from the
lateral and upper part of the arytaenoid cartilage ;
and, running along the outer side of the external
rima, is

Inserted into the epiglottis along with the former.

Use. To pull that side of the epiglottis towards
the external rima ; or, when both act, to pull it
close upon the glottis. It is counteracted by the
elasticity of the epiglottis.



CHAP. XV.

MUSCLES SITUATED ON THE ANTERIOR
PART OF THE ABDOMEN.

THEY consist of three broad layers on each side



* Before commencing this dissection, the abdomen should be in-
flated through the umbilicus. This will render the dissection easier
to the young student, and give a fine appearance to the muscles. An
incision should then be made through the skin, from the sternum to
the pubis, and crossed by another at right angles about the umbilicus.
If the skin only be dissected off, a view will be obtained of the facia
superficialis, as it is called. It is not deserving the name of a facia,
but is just a layer of cellular and fatty matter, which connects the
skin to the subjacent parts ; and in which a number of lymphatic
glands near the groin are embedded. By removing the facia super-
ficlalis the abdominal muscles are exposed.

In dissecting the external oblique muscle, many important cir-



46 DESCRIPTION OF

of the belly; always a long one, and generally also
a short one, on each side of the linea alba.

The three layers are,

1. OBLIQUUS DESCENDENS EXTERNUS,

Arises, by eight heads, from the lower edges of
an equal number of inferior ribs, at a little distance
from their cartilages: it always intermixes, in a



cumstances are to be noticed, viz. the exact situation of the abdomi-
nal ring ; its form ; its relation to the pubis ; to Poupart's liga-
ment ; the small membrane which closes it up, and the effects
which, a hernia, might be supposed to have, both on the ring and
this membrane. The inferior margin of this muscle ought now to be
completely exposed, and the parts which pass under it minutely ex-
amined. These are muscles, vessels, and a nerve. The vessels and
nerve will be found lying nearer the pubis than the muscles, and in
the following order. The lymphatic vessels nearest the pubis, and
in contact'with Gimbernaut's duplicature ; the femoral vein upon
the outside of the lymphatics ; the femoral artery upon the outside
of the vein, but closely connected to it ; and the anterior crural nerve
still farther removed from the pubis. When the obliquus externus
has been fully examined, it should be detached from the ribs and
Poupart's ligament, and carried forwards to the linea semilunaris,
that the muscle below may be displayed. This dissection will likewise
expose the inguinal canal, and the spermatic cord lying in it. The
cord will be discovered passing from under the inferior margins of
the internal oblique and transversalis, and running for more than an
inch behind the tendon of the external oblique, till it issues out at
the external inguinal opening.

The removal of the internal oblique so as to bring into view the
transversalis, requires some caution. The dissection should com-