Oskar Schultze.

Atlas and text-book of topographic and applied anatomy online

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Fig, 9.




Facial n.
Auditory
Glossopharyngeal



Orbital plate of frontal bon
Cribriform plate of ethmoid



Lesser wing of the sphenoid
bone

Great wing of the sphenoid bo
Trochlear nerve

Ophthalmic nerve
Oculomotor nerve
Superior maxillary nerve
Abducent nerve

.Inferior nurxillary nerve

Squamous portion of

temporal bone
Internal auditory meatus

Anterior condyloid foramen
Jugular foramen



Parietal bone
Groove for lateral ;
Straight sinus



Lateral sinus
Torciilar Herophili ,
Occipital bone



THE MEMBRANES OF THE BRAIN. 33

The nerves most apt to give rise to symptoms are the facial (paralysis of the muscles of expression)
and the auditory in fracture or caries of the petrous portion of the temporal bone, the abducent
and the oculomotor, and more rarely the trochlear, the trifacial, and the optic. Tumors situated
at the base of the skull may press upon the nerves having a subdural or an intradural course and
consequently lead to more or less severe pressure-symptoms dependent upon the particular nerve
affected.

Under certain circumstances olfactory or visual disturbances may point to the presence of
a tumor in the anterior cranial fossa; symptoms of pressure upon the semilunar ganghon and
disturbances of the muscles of the eye may Hkewise indicate a growth in the middle cranial fossa.
If the trunk of the trifacial is pressed upon before it perforates the dura, and if the facial and
hypoglossal nerves are compressed at the base of the skull, we are justified in locating the lesion
in the posterior cranial fossa, while symptoms pointing to the pons or cerebellum would demand
the same localization. Since the division of the fifth cranial nerve into its three branches takes
place within the cranial cavity, any one of these branches may be affected by diseases of the inner
surface of the base of the skull.

The arachnoid membrane (the second of the brain membranes) (see Fig. 7) is separated
from the dura by the subdural space. The pia mater is separated from the arachnoid by the
subarachnoid space which is filled with the cerebrospinal fluid. Numerous trabeculae pass across
this subarachnoid space and form an intimate connection between the arachnoid and pia, par-
ticularly at the convexities of the cerebral convolutions. While the non-vascular arachnoid
bridges over the sulci between the convolutions, the pia mater carrying the ramifications of
the blood-vessels dips into the sulci and is intimately attached to all portions of the surface
of the brain. In several places, particularly at the base of the brain, there are comparatively
large spaces between the arachnoid and the pia, and these are known as the cisternce sub-
arachnoideales. There is no communication between the subdural and the subarachnoid space,
but the subarachnoid space freely communicates with the ventricles of the brain [through
an opening in the roof of the fourth ventricle, and also at the extremity of the descending horn
of the lateral ventricle. — Ed.].

It consequently follows that the cerebrospinal fluid in the ventricles may be drawn off after
the subarachnoid space has been opened.

The arachnoid membrane, particularly in the vicinity of the superior longitudinal sinus,
possesses variously formed villi, groups of which may be seen projecting into the interior of the
sinus or its lateral recesses when this venous channel has been laid open. They act as normal
places of drainage for the cerebrospinal fluid. When they become hypertrophied they form the
Pacchionian bodies, which are lodged in the Pacchionian depressions (see page 18).

The larger branches of the cerebral vessels are found in the subarachnoid space. Effusions
of blood in this space come either from the cerebral vessels or from the vessels of the dura, in which
latter case, a rupture of the arachnoid must, of course, have taken place (see page 29). The
relation of the arteries to definite portions of the base and to definite cranial nerves (see Plate 3)
makes it clear that aneurysm of these arteries must produce definite locahzing symptoms of cere-
bral compression.

The arterial supply of the brain is furnished by the vertebral and internal carotid arteries
3



34 TOPOGRAPHIC AND APPLIED ANATOMY.

Fig. io. — The Gasserian ganglion (ganglion semilunare) which has been exposed in the middle cerebral fossa by
the removal of the dura mater.

Fig. II. — Frontal section in the region of the cavernous sinus.

which form the circle of WilUs, situated in the subarachnoidean space at the base of the brain in
the region of the interpeduncular space (see Plate 3).

The vertebral artery, soon after its origin from the subclavian (see Fig. 27), enters the foramen
in the transverse process of the sixth cervical vertebra, passes through the transverse processes of
all of the overlying cervical vertebras, runs toward the median line in the groove upon the upper
surface of the posterior arch of the atlas, perforates the posterior occipito-atlantal ligament and
the dura, and reaches the anterior surface of the medulla oblongata, at the superior boundary of
which it unites with the vessel of the opposite side to form the basilar artery. This artery lies in
the basilar groove of the pons, and at its superior margin divides into two terminal branches, the
posterior cerebral arteries.

The internal carotid artery, commencing at the bifurcation of the common carotid at the
level of the upper margin of the thyroid cartilage, gives off no cervical branches, but ascends to the
base of the skull along the lateral wall of the pharynx. It is separated from the external carotid
artery by the styloglossus and stylopharyngeus muscles. It pursues a curved course through
the carotid canal of the petrous portion of the temporal bone (see Fig. 23), the concavity of the
curve being directed anteriorly. This leads us to remark that fatal hemorrhage has been ob-
served from the internal carotid artery in cases of caries of the petrous portion of the temporal
bone. After lea^'ing the carotid canal the vessel passes across the middle lacerated foramen in
the carotid sulcus at the side of the body of the sphenoid bone and is enclosed in the cavernous
sinus. It then ascends to the optic foramen, where it describes a short curve, convex forwards,
from which is given off the only branch not supplying the brain, the ophthalmic artery, which,
together with the optic nerve, enters the orbital cavity through the optic foramen. After pene-
trating the dura, the internal carotid artery reaches the base of the brain at the angle between the
optic nerve and the optic tract, where it divides into two main branches, the anterior and
middle cerebral arteries.

The chief branches of the vertebral and basilar arteries which supply the brain are :

1. The posterior inferior cerebellar artery, from the vertebral to the lower surface of the
cerebellum.

2. The anterior inferior cerebellar artery, from the basilar to the lower surface of the cere-
bellum.

3. The superior cerebellar, which arises from the basilar at the anterior margin of the pons
and ramifies upon the superior surface of the cerebellum.

4. The posterior cerebral arteries, the two terminal branches of the basilar. This vessel is
separated from the superior cerebellar at its origin by the oculomotor nerve and supplies the occip-
ital lobe and the greater portion of the temporal lobe. It is connected with the internal carotid
by the posterior communicating artery.

5. The internal auditory artery, which reaches the internal ear through the internal auditory
meatus.

The vertebral artery also gives off lateral spinal branches in the neck which pass into the



Fig, 10.



Oculomotor n
Trochlear nerve i
Left posterior cerebral artery i
Right posterior cerebral artery
Aqueduct of Syl'
Tentorium cerebelli
Straight sinus ; Crura ccreb;



Posterior communicating artery
Abducent nerve




FlQ. II.



Optic ne
Internal carotid




CRANIOCEREBRAL TOPOGRAPHY. 35

vertebral canal through the intervertebral foramina, meningeal branches to the dura mater in the
posterior cerebral fossa, and the anterior and posterior spinal branches to the spinal cord and its
membranes.

The internal carotid arterj- suppHes the brain with:

1. The anterior cerebral artery. It passes inward over the dorsal surface of the corresponding
optic nerve and then forward, approaching the artery of the opposite side, with which it is con-
nected by the anterior communicating artery. The vessels winding around the genu of the corpus
callosum pass backward, supplying the corpus callosum, and ramify upon the median surface
of the cerebral hemispheres.

2. The middle cerebral artery, which runs in the fissure of Sj-lvius, supplying the frontal,
parietal, and temporal lobes as well as the island of Reil.

3. The anterior choroid artery, passing posteriorly along the optic tract to the descending
horn of the lateral ventricle to enter the choroid plexus.

4. The posterior communicating artery, which has been previously mentioned.

CRANIOCEREBRAL TOPOGRAPHY.
The tentorium cerebelli (see Figs. 2, 9, 17, and Plate 4) divides the cranial cavitv into two
closed spaces which communicate with each other through the incisura tentorii. The larger
anterior space includes the anterior and middle cranial fossas and lodges the cerebrum; the
small posterior space— the posterior cranial fossa— contains the cerebellum, the pons, and the
medulla. A frontal section through the back part of the head, posterior to the incisura tentorii
(see Fig. 12), reveals four separate compartments having apparently no connection with each
other, since the falx cerebri, the falx cerebelli, and the tentorium form a cross-like partition
which separates the hemispheres of the cerebrum and cerebellum. The plane of such a cross-
section will be better understood after a study of other illustrations (Fig. 9, Plate 4). The
following relations will be made more clear to the mind of the reader by looking at the base of
a skull (see Fig. 9 and Plate i).

The anterior cranial jossa lodges the frontal lobes of the cerebrum; the marked develop-
ment of the juga (ridges) cerebralia and of the impressiones digitate on the tliin orbital plate of
the frontal bone are due to the orbital sulci and gyri respectively. In the median line the
olfactory bulb rests upon the cribriform plate of the ethmoid and gives off the olfactory filaments
to the nasal cavity.

The middle cranial fossa contains the temporal lobes. Its posterior and lateral portion bears
an important relation to the roof of the middle ear (tegmen tympani). This is the situation at
which abscesses develop in the temporal lobes as the result of suppurations in the middle ear.
Another important situation in the middle cranial fossa is located anterioriy near the median line,
where the large semilunar ganghon is found with its three main divisions (see page 32). The pos-
terior border of the lesser wing of the sphenoid corresponds to the deep fissure of Sylvius situated
between the frontal and temporal lobes. The optic chiasm, giving off the optic nerves, is situated
anteriorly in the narrow median portion of the middle cranial fossa. Further posteriorly, the
hypophysis cerebri is imbedded in the sella turcica.



36 TOPOGEAPHIC AND APPLIED ANATOMY.

PLATE 3.

The base of the brain with the twelve cranial nerves and the cerebral arteries.

The incisura tentorii transmits the so-called isthmus cerebri, which is formed ventrally by
the crura and dorsally by the corpora quadrigemina. The occipital lobes of the cerebrum rest
upon the tentorium; the lower surface of the tentorium covers the upper surface of the cere-
bellum, the hemispheres of which fill the deepest portions of the posterior cranial fossa (fossae
occipitales). The pons lies upon the upper two-thirds of the clivus, its anterior border almost




Occipital lobe



Fig. 12. — A frontal section through the posterior portion of the head (frozen section). Anterior view. The
section strikes the fal.\- cerebri, the falx cerebelli, and the tentorium cerebelli in such a way that the cranial cavity seems
to contain four apparently separate compartments, in which may be seen the two cerebral and the two cerebellar
hemispheres.

reaching to the dorsum of the sella turcica. The lower third of the chvus, as far down as the
foramen magnum, lodges the anterior portion of the medulla oblongata which extends to the
upper margin of the posterior arch of the atlas. A median sagittal section (see Plate 4) shows
that the pons and medulla assume an almost vertical position. It should also be observed that the
cerebrum is much more exposed to external injuries than is the better protected cerebellum.

As it is occasionally necessary to open the cranial cavity and expose definite regions of the



Superior longitudiAal



N. Optic n,
i . Hypophysis
". Temporal lobe
Oculomolor
Trochlear

Trifacial nerve
Abducent nerve

Auditory
Facial
Glossopharyngeal n,
Pueumogastric n

Spinal accessory n,
Medulla oblongat




Occipitalis muscle



LA IE a.
' Ive cranial nerves :



the crura and (lunsu|]jV^]^M;ho_cor^



upon the tentorium; the l(»wcj>^rfacc of the tentorium covers the
bellum,* the heyAkplaft- ^-s ()^/(\'hic h fill the deepest p ortiono of the pn^fnrr .
occlnitnlcs-i. 'The T^ors ]Ks udoii the' upper two-thirds of the clivus, it




called isthmus cerebri,
lina. The



lol>i-o e



Hinder ;;lraost




-DIM Am .iaA ,

ijiDJie IfiidanoV

-3133 .ini .leo*I

Yianii icllad

kdicr? ^oi-^3)^A

fraJTR



saod Ifi}iqi330




udol liiioqmaT
<n loiomoIuDO

.3V13n lI13lri30lT



3VT3a (cisiilnT
avion Ja33ijbdA



— yvTjfl ^lojibuA-

n Icayn-iifidqaaaoIO ,
- . a 3i-aa£3omu9n*I

IcniqS



£j£3no(do ^liubsW



?iiiiia



3bauni aiifiiqiosO



r -aching lo tlu V-iii,-; of the m:-1ui
foramen magn' 'he anterior portion ot the medulla ol ■

111)1 xr ir..ii-"in iir rrh of the atlas. A ]n.iUap -a/!''

i;. an almost veni




uortion of the head (frozen sociion
ri'helli in surh aw,



may be seen the two 'xi



h-di the
nite regions of th



Tab.:i-



Sinus sagittalis sup.-



Lobus frontalis l...ali,

la,



M. frontalis
- -Os frontale



N. opticus.

Hypophysis

Lobus temporalis

N. oculomotorius

N. trochlearis ..

N. trigeminus
N. abducens

N. acusticus.

N. facialis

N. glossopharyngeus
N. vagus

N. accessorius
Medulla oblongata




Dura mater



Bulbus olfactorius



M. temporalis
Tractus olfactorius



A.communicans ant.
A. cerebri anterior

A. cerebri media
A.carotis interna
A.communicans post.

A. cerebri post.
A. cerebelli sup.
Os parietale
— Pons



A. cerebelli inf. ant.
A. basilaris
A. vertebralis

/ A. cerebelli inf. post.
A. spinalis ant.



Os occipitale



Sinus occipitalis



M. occipitalis



CRANIOCEREBRAL TOPOGRAPHY.



37



cerebral surface (in cases of cerebral abscess, tumors, and operations upon the cortex), the surgeon
needs certain lines as aids in the localization. In consequence of the manifold variations in the
shape of the skull, these lines are not absolutely accurate in all cases, but they nevertheless furnish
indispensable guides. An exact topographic locahzation is never possible until the surgeon has
made an extensive opening in the skull and exposed the cerebral surface. Kronlein recommends
the following lines (see Fig. 13):




Fig. 13. — Craniocerebral topography (after Kronlein and Froriep). Explanation in the text.



1. The base-line (horizontal line, ear-orbit line) through the infraorbital margin and the
upper border of the external auditory meatus (Reid's base-line).

2. The superior horizontal line through the supraorbital margin, parallel to the base-line
(line of Kronlein).

3. The anterior vertical line, at right angles to the base-line at the middle of the zygoma.



38 TOPOGRAPHIC AND APPLIED ANATOMY.

4. The middle vertical line, at right angles to the base-hne from the condyloid process of the
mandible.

5. The posterior vertical line at right angles to the base-line from the most posterior portion
of the base of the mastoid process.

If the point of intersection of the anterior vertical with the superior horizo;ital line is connected
with the point where the posterior vertical line strikes the vertex [that is, the antero-posterior
median Hne of the vertex. — Ed.], we have:

6. The linea Rolandi, corresponding to the fissure of Rolando.

If the angle formed by the superior horizontal Hne with the line of Rolando is bisected and
the bisecting line is extended to the posterior vertical line, we have :

7. The linea Sylvii, corresponding to the fissure of Sylvius.
The following is an explanation of the letters in Fig. 13:

K, Junction of the horizontal with the vertical limb of the fissure of Sylvius.

S, Upper end of the fissure of Sylvius.

R, Lower end of the fissure of Rolando.

K and K', indicate the two trephine openings of Kronlein for the anterior and the posterior
branches respectively of the middle meningeal artery (see page 29). The rectangle ABK'M
corresponds to the area resected by v. Bergmann as a preliminary step to operative measures
in the middle cerebral fossa.

QUESTIONS.

How should the frontal sinus be opened in order to reach its communication with the nasal cavity ?

^Vhat fontanelles are felt in the head of the new-born ?

How may subcutaneous emphysema be produced after the frontal sinuses have been opened ?

To what extent may the withdrawal of blood from the scalp — from behind the ear, for example
— aid in diminishing increased intracranial blood-pressure ?

^^'hich cranial nerves are, as a result of their course, particularly apt to be affected in basal frac-
tures and compressed against the base by tumors ? What is characteristic of this course ?

From what situation in the face is it possible to wound the brain without a concomitant injury of
the cranial bones?

Is the escape of blood or cerebrospinal fluid from the nose, in cases of basal fractures, of any value
in localizing the seat of the fracture ? If not, why ? What vessels may be involved ?

Where are the places at the base of the skull which are pushed against the brain by tumors growing
from the sphenoidal sinus or from the ethmoidal cells ? Find these places in the illustrations.

^^^lat difference exists between the skin of the scalp and the scalp proper, and how is the mova-
biHty of both affected by their anatomic structure ?

Why is it that cutaneous wounds of the scalp do not gape while wounds involving the entire
scalp do?

Why is it impossible to close large cutaneous defects in the scalp by uniting the edges of the wound ?

What are the characteristics, dependent upon anatomic structure, of an effusion of blood or of a
suppuration in the scalp ? Beneath the scalp ?

Why does the skin of the scalp bleed more profusely after injury than that of any other cutaneous
area ? Why do large flaps in this situation adhere more readily than elsewhere ?



THE FACE. 39

Where may the pulsations of the temporal artery be felt ?

In what situations may neurectomy of the supraorbital and of the occipitalis major nerves be per-
formed ?

Into what cleft-like spaces may the blood be poured from a wound of the middle meningeal artery ?

What are the locations of the trephine openings for both branches of the middle meningeal artery?

How is access to the lateral sinus best gained from the exterior ? What is the relation of the
lateral sinus to the mastoid cells ?

What is the explanation of the symptom of pulsating exophthalmos ?

How is the semilunar ganghon best exposed from the outside of the skull, and what neighboring
structures are thereby endangered ?

Which cranial nerves and which large arteries are endangered in fractures of caries of the petrous
portion of the temporal bone ?

Which lobe of the brain lies upon the tegmen tympani? Why is it important to know this?

THE FACIAL REGION.
THE FACE.

The skin of the face, on account of its thinness and vascularity, furnishes the physician with
an important diagnostic aid in forming a conclusion as to the general condition of his patient
(redness, paleness, cyanosis). In contrast to the sldn of the scalp (see page 24), it possesses great
movability, which, together with its vascularity, markedly favors the performance of plastic
operations. The connection of the skin with the muscles of expression is a further character-
istic demanding attention. Effusions of blood into the loose subcutaneous tissue spread dif-
fusely, so that sharply circumscribed swellings are not observed after contusions; in dropsy the
entire face may be swollen. [Because of its vascularity facial wounds, even when much lacerated
and contused, heal rapidly. — Ed.]

The bony framework of the face, the facial skeleton, is composed of the fourteen facial bones.
Six of these are paired: the superior maxilla, the palatine, the malar, the nasal, the lachrymal,
and the inferior turbinated bones. The remaining two are single bones, the inferior maxilla
and the vomer. The bones as well as the large portion of the ethmoid entering into the facial
skeleton should be reviewed in a systematic text-book and with specimens ; the same is true of the
muscles of expression and of mastication.

Arteries. — Disregarding the branches which extend into the face from the vessels of the
cranial region, the four main trunks particularly supplying the face are :

1. The facial artery, from the external carotid (see Plate 2).

2. The internal maxillary artery, one of the terminal branches of the external carotid.

3. The ophthalmic artery, from the internal carotid (see Plate 18).

4. The lingual artery, from the external carotid (see page 64).

In addition to these vessels, there are some small branches of the temporal artery, such as
those passing to the parotid gland and to the auricle, as well as the transverse facial artery below,
and the orbital artery above, the zygoma (Plate 2).

The facial artery in the neck runs in the submaxillary triangle, imbedded in the substance of
the submaxillary gland [imbedded in a groove on the posterior end of the submaxillary gland, which



40 TOPOGRAPHIC AND APPLIED ANATOMY.

Fig. 14. — The relations of the vessels and of the facial nerve within and beneath the parotid gland. The gland has
been divided by a vertical incision.

separates it from the more superficial facial \-ein (Cunningham). — Ed.], and crosses the border of
the jaw at the anterior margin of the masseter muscle. At this point the pulsations of the vessel
may be felt and, in a given case, hemorrhage may be temporarily arrested by pressure against the
jaw-bone. The artery then pursues a more or less sinuous course upon the buccinator and
levator anguli oris muscles and reaches the side of the nose, where it anastomoses, as the angular
artery, with the dorsalis nasi artery coming out of the orbit from the ophthalmic. It also forms
variable anastomoses with the buccal and infraorbital branches of the internal maxillary. In
the neck the vessel gives off the ascending palatine artery, frequently an independent branch
of the external carotid, which ascends between the styloglossus and stylopharyngeus muscles to
the muscles of the palate and pharynx, giving off a tonsillar branch (see page 57); the submental
is another cervical branch which passes forward below (f. e., on the outer surface of) the mylo-
hyoid muscle and is covered by the submaxillary gland. In the face the artery gives off the
superior and inferior coronary arteries which supply the mucous membrane of upper and lower
lips and anastomose in the median line with their fellows of the opposite side.

The internal maxillary artery, one of the terminal branches of the external carotid, arises
in the substance of the parotid gland behind the neck of the condyle of the lower jaw and
passes to the spheno-maxillary fossa. The branches worthy of mention, in addition to those
supplying the muscles of mastication, are the inferior dental (passing though the inferior dental
canal in company with the nerve of the same name and escaping from the mental foramen), the
middle meningeal (see page 29), the infraorbital (passing through the infraorbital canal with the
nerve of the same name to make its exit at the infraorbital foramen), the superior alveolar to the
teeth of the upper jaw, the posterior palatine and the pterygopalatine to the palate (naso-pharynx)
(through the foramina of the same name), and the sphenopalatine, which passes through the
sphenopalatine foramen to the nasal cavity.

The chief vein of the face is the facial, which commences as the angular vein, formed by the



Online LibraryOskar SchultzeAtlas and text-book of topographic and applied anatomy → online text (page 4 of 29)