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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4501_Библиотеки_им_академика_М_И_Перельмана
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10 ■ ANATOMY OF THE TEMPORAL BONE WITH SURGICAL IMPLICATIONS
Figure 12
Note the normal thinness of the skin lining the anterior wall of the bony external auditory canal. The fibrous annulus
of the tympanic membrane is seated
within its bony sulcus. The manubrium
narrows as it extends downward. The
incudostapedial articulation is seen. The
bone that overlies the facial nerve protrudes toward the oval window niche,
forming the pyramidal eminence which
houses the stapedius tendon. The tendon attaches to the head of the stapes.
The saccule is seen at the anteromedial
aspect of the perilymphatic cistern of
the vestibule. The glial-Schwann sheath
junctions of the cochlear and vestibular
nerve trunks are seen in the internal
auditory canal.
Figure 13
The manubrium and inferior tip of
the long process of the incus are seen.
The facial nerve continues its descent
in its fallopian canal. The posterior
semicircular canal remains visible. The
utricle narrows as the nonampullated
end of the lateral duct enters at the
utricular crest. The saccular nerve traverses the cribrose area to the saccular
macula. The carotid artery is surrounded by a connective tissue sheath
in which the pericarotid venous plexus
and pericarotid sympathetic nerve
plexus are embedded. The sigmoid sulcus is visible posteriorly.
Figure 11
The manubrium continues its descent
separated from the pars tensa by a
mucosal fold. The stapes is now
evident in its characteristic stirrup
form. The facial nerve descends in its
mastoid segment. The protympanum
extends anteriorly from the
mesotympanum. The apical turn of the
cochlea is visible as well as the helicotrema which marks the wide communication of the scala tympani and
scala vestibuli. The nonampullated end
of the membranous lateral semicircular
duct enters the utricle.
CHAPTER 1: SERIAL PHOTOGRAPHS OF SECTIONS OF THE TEMPORAL BONE ■ 11
Figure 14
The tympanic membrane is circumferentially fixed by the tympanic
annulus to the walls of the tympanic
sulcus. The singular canal carries the
posterior ampullary nerve, a branch of
the inferior division of the vestibular
nerve, to the ampulla of the posterior
canal. The vestibular aqueduct containing the endolymphatic (otic) duct
approaches the dura. Shielding its exit
is a thin scale of bone, the operculum.
Figure 15
The umbo marks the approximate
center of the tympanic membrane and
corresponds to the end of the
manubrium which at this level is
completely enveloped by the pars
propria of the tympanic membrane.
The basal turn of the cochlea turns into
the vestibule. The ductus reuniens
links the cochlear duct and saccule. The
singular canal is seen traveling toward
the ampullated end of the posterior
canal.
Figure 16
The internal auditory canal gradually
recedes from view as does the middle
turn of the cochlea. The bony wall of
the basal turn forms the promontory on
the medial wall of the middle ear.
12 ■ ANATOMY OF THE TEMPORAL BONE WITH SURGICAL IMPLICATIONS
Figure 18
The round window niche lies inferior
to the promontory. The tympanic
ostium of the cochlear aqueduct is
situated at the posteromedial aspect
of the basal turn of the cochlea. The
subiculum is a ridge of bone that
defines the inferior limit of the sinus
tympani. The lumen of the bony
posterior semicircular canal is
seen with the ampullated and
nonampullated ends of the
membranous duct. Anteriorly lies
the petrous apex containing, in this
case, highly cellular marrow.
Figure 19
The pericarotid venous plexus is visible
on both the anterior and posterior
aspects of the internal carotid artery.
The peritubal air cells comprise the lateral components of pneumatization of
the petrous apex region.
Figure 17
The facial nerve continues its descent
in the mastoid segment of the fallopian
canal. Only the basal turn of the
cochlea remains visible. The scala tympani of the basal turn lies adjacent to
the round window membrane. The
endolymphatic sac lies between
two layers of dura in its foveate fossa,
paralleling the posterior wall of the
temporal bone.
CHAPTER 1: SERIAL PHOTOGRAPHS OF SECTIONS OF THE TEMPORAL BONE ■ 13
Figure 20
The anatomic juxtaposition of the
stapedius muscle and the facial nerve is
evident. The bony posterior semicircular
canal recedes from view. The cochlear
aqueduct proceeds posteroinferiorly
toward the subarachnoid space.
14 ■ ANATOMY OF THE TEMPORAL BONE WITH SURGICAL IMPLICATIONS
VERTICAL TWO-DIMENSIONAL SERIAL PHOTOGRAPHS
The following series of photomicrographs (Figs. 21–37) show the right temporal bone of a 32-year-old female as it appears in vertical cross section, cut
perpendicular to the long axis of the petrous bone. Vertical sections are smaller
than horizontal sections but there are more of them. The trimmed specimen
cut at 20 m generates about 800 sections and every 10th is stained and
mounted on glass slides. In this case, two vertical sections can be mounted on
each 1inch ⫻ 3inch slide, resulting in a final series of about 40 such slides.
Vertical sections are particularly useful for the study of pathologic conditions
located in the most superior and inferior parts of the temporal bone.
The sections are arranged sequentially from posterolateral to anteromedial; approximately every 50th section has been selected for this series.
The tegmen lies superiorly separating the mastoid and middle ear from the
temporal lobe. The posterior cranial fossa is located posteriorly. The carotid
canal and jugular vein are seen inferiorly, the external auditory canal laterally, and the middle ear space medially. The inner ear structures begin with
the canals, then the vestibule, and finally the cochlea.
Figure 21
The external auditory canal (EAC) is seen in
cross section. The chorda tympani nerve heads
anteriorly and laterally toward the tympanic
cavity. The bony posterior canal is opened and
its enclosed duct is seen. The break in the
tegmen of the mastoid is an artifact of preparation.
CHAPTER 1: SERIAL PHOTOGRAPHS OF SECTIONS OF THE TEMPORAL BONE ■ 15
Figure 22
The facial nerve descends in its mastoid segment and the
chorda tympani nerve approaches the iter chordae posterius.
The short process of the incus is tethered in the incudal fossa by
the posterior incudal ligament. The lateral canal is now evident;
an extension through its long axis bisects the posterior canal.
Cells of the supralabyrinthine area are visible posterosuperiorly. Posteriorly, the endolymphatic sac is capped by the operculum. The retrofacial group of mastoid air cells is seen.
Figure 23
Progressing anteromedially, the tympanic membrane, tympanic
sulcus, and fibrous annulus come into view. The stapedius muscle is inferior and posterior to the facial nerve.
16 ■ ANATOMY OF THE TEMPORAL BONE WITH SURGICAL IMPLICATIONS
Figure 24
The incus is now visible in the epitympanum. The chorda
tympani nerve crosses the tympanic cavity suspended in a
mucosal fold. The tympanic segment of the facial nerve lies
inferior to the lateral canal.
Figure 25
The division of the tympanic membrane into a pars flaccida
superiorly and a pars tensa inferiorly can be seen. The space
superior to the lateral process of the malleus, medial to the pars
flaccida, is Prussak’s recess. The incus articulates with
the malleus in a cog wheel fashion.
CHAPTER 1: SERIAL PHOTOGRAPHS OF SECTIONS OF THE TEMPORAL BONE ■ 17
Figure 26
The chorda tympani nerve now is closely applied to the medial
aspect of the neck of the malleus. Extending laterally from the
neck of the malleus is the lateral malleal ligament. The lenticular process of the incus articulates with the head of the stapes.
Within the perimeter of the superior semicircular canal one can
see the petromastoid canal with its subarcuate vessels. The
opening in the canal is an artifact.
Figure 27
The ampulla and crista of the superior canal are visible. Inferior
to the oval window niche is the bulge of the promontory.
18 ■ ANATOMY OF THE TEMPORAL BONE WITH SURGICAL IMPLICATIONS
Figure 29
The facial nerve is located just superior to the tendon of the tensor tympani muscle. The utricle and saccule now come into
view. The scala vestibuli opens into the vestibule. The peaked
configuration at the posterior aspect of the scala tympani is the
tympanic orifice of the cochlear aqueduct. The singular canal
contains the posterior ampullary nerve.
Figure 28
Superior to the external auditory canal (EAC) is the petrotympanic fissure. Lateral to the facial nerve, the tendon of the tensor
tympani muscle lies in the concavity of the cochleariform
process. The round window niche and membrance are
emerging.
CHAPTER 1: SERIAL PHOTOGRAPHS OF SECTIONS OF THE TEMPORAL BONE ■ 19
Figure 30
The external auditory canal dwindles. Running medially from
the scala tympani is the cochlear aqueduct. There is extensive
infralabyrinthine pneumatization.
Figure 31
The facial nerve is seen in its labyrinthine segment as well as
at its genu.
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