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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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50 ■ ANATOMY OF THE TEMPORAL BONE WITH SURGICAL IMPLICATIONS
Figure 18
The lateral process of the malleus has a
cartilaginous cap which facilitates separation of the malleus from the tympanic membrane in this region (male,
age 72yr).
Figure 19
At the umbo, the lamina propria splits to
envelop the manubrium of the malleus,
making it difficult to separate the
malleus from the tympanic membrane
without perforation (male, age 28yr).
CHAPTER 3: THE MIDDLE EAR ■ 51
Figure 20
At its mid-portion, the manubrium is
normally separated from the tympanic
membrane by a mucosal fold (the
manubrial fold or plica mallearis)
(male, age 63yr).
Figure 21
In the anteroposterior dimension, the
manubrium is normally located near
the middle of the tympanic membrane
(male, age 87yr).
52 ■ ANATOMY OF THE TEMPORAL BONE WITH SURGICAL IMPLICATIONS
Figure 22
In this ear, the manubrium is positioned
anteriorly in the tympanic membrane.
While this anatomical variant is compatible with normal hearing, it increases
the risk of fibrous fixation of the malleus
following myringoplasty (male, age
79yr; see Figs. 8 and 9 on p. 45).
Figure 23
Except at the umbo, the manubrium is
oval-shaped, an anatomical feature that
must be considered in the design of
prostheses that attach to it (male, age
28yr).
Figure 24
Midway between the lateral process
and umbo, the manubrium is separated
from the tympanic membrane with
only the manubrial fold of mucous
membrane joining them. This is the
ideal location for attachment of prostheses (female, age 60yr).
CHAPTER 3: THE MIDDLE EAR ■ 53
Figure 25
Attachment of a prosthesis (e.g., teflon
wire piston) to the oval-shaped manubrium requires a longer loop than is
needed for the circular-shaped long
process of the incus. The fabrication of
such a loop is illustrated in this figure.
The black semicircles represent the
jaws of a small forceps (78).
Figure 26
The metallic prosthesis is firmly attached
to the manubrium in a wrap-around
manner. A loose attachment invariably
results in traumatic osteitis and extrusion of the prosthesis (78).
54 ■ ANATOMY OF THE TEMPORAL BONE WITH SURGICAL IMPLICATIONS
Figure 27
The anterior and lateral suspensory ligaments of the malleus are shown. The
notch in the short process of the incus,
originally described by Lempert and
Wolff (79), is well visualized; its derivation and function (if any) is not known
(male, age 77yr).
Figure 28
The lateral suspensory ligament of the
malleus extends from the neck of the
malleus to the bony margin of the
notch of Rivinus (male, age 65yr).
The malleus is held in place by five ligaments, one articulation, the tensor
tympani tendon, and the tympanic membrane. Three of the five ligaments
are well outside the axis of rotation and have a suspensory function; they
are: (1) the anterior suspensory ligament which lies superior to the anterior
malleal ligament and attaches the head of the malleus to the anterior wall of
the epitympanum (Fig. 16), (2) the lateral suspensory ligament (Figs. 27
and 28) which attaches the neck of the malleus to the bony margins of the
tympanic notch (the notch of Rivinus), and (3) the superior suspensory
CHAPTER 3: THE MIDDLE EAR ■ 55
Figure 29
The thickened, inferior portion of the
posterior malleal fold forms the posterior malleal ligament. It stretches from
the neck of the malleus to the pretympanic spine (female, age 64yr).
ligament which bridges the gap between the head of the malleus and the
tegmen of the epitympanum.
These ligaments apparently do not interfere with sound transmission
because of the small movement of the ossicles. They may be useful in damping the response of the ossicles to low frequency stimuli of high intensity and
in resisting ossicular displacement with large changes in middle ear pressures. The anterior malleal ligament, in concert with the anterior process of
the malleus, is in the axis of ossicular rotation. The posterior malleal ligament (Fig. 29) is the thickened inferior margin of the posterior malleal fold
and stretches from the neck of the malleus to the pretympanic spine. The
tympanic membrane attaches the manubrium to the tympanic sulcus.
Additionally, the malleus is tethered by the capsule of the incudomalleal articulation which features two thickenings known as the medial and
lateral incudomalleal ligaments and by the capsule of the incudostapedial
articulation.
The tendon of the tensor tympani muscle extends laterally from the
cochleariform process to attach to the neck and manubrium of the malleus.
Often some of its fibers pass anterior to the manubrium to reach the tympanic membrane (Figs. 30–32). The function of the tensor tympani muscle is
to pull the manubrium medially and thus exert tension on the tympanic
membrane.
Normally, the pull of the tensor tendon is opposed by the elasticity of
the pars propria. With a large perforation of the tympanic membrane,
the unopposed pull of the tensor tendon causes a medial displacement of
the inferior end of the manubrium (Figs. 33 and 34). In some cases, the
manubrium may eventually reach the promontory. In surgical reconstructive procedures, such as myringoplasty, it may be prudent to section the
tensor tendon prior to manipulating the manubrium back into its normal
position.
56 ■ ANATOMY OF THE TEMPORAL BONE WITH SURGICAL IMPLICATIONS
Figure 30
In this ear, the tensor tympani tendon
attaches to the tympanic bone as well
as to the neck of the malleus (male, age
81yr).
Figure 31
In addition to inserting into its normal
position on the posterior aspect of the
neck of the malleus, a small slip of the
tensor tendon extends laterally to
the tympanic membrane. Anteriorly,
the canal of Huguier transmits the
chorda tympani nerve as it leaves the
petrotympanic (Glaserian) fissure.
A stapedectomy for otosclerosis had
been performed (male, age 72 yr;
see Fig. 32 on p. 57).
CHAPTER 3: THE MIDDLE EAR ■ 57
Figure 32
High-power view of outlined area of
Figure 31 on p. 56.
Figure 33
This subject had a long history of recurrent otorrhea. There is a perforation of
the tympanic membrane and displacement of the manubrium toward the
promontory (male, age 35yr).
58 ■ ANATOMY OF THE TEMPORAL BONE WITH SURGICAL IMPLICATIONS
Figure 34
With a large perforation of the tympanic membrane, the tensor tympani
muscle acts with diminished opposition which eventually results in medial
displacement of the manubrium
(female, age 74yr).
Figure 35
A bony spur extends from the lateral
wall of the epitympanum to approximate the lateral aspect of the head of
the malleus, causing no apparent
hearing loss (female, age 22yr).
Frequently, there are projections of bone from the anterior and superior
walls of the epitympanum which approximate the head of the malleus. In
some instances, only a thin layer of loose fibrous tissue separates them
(Figs. 35–40). Davies (13) reasoned that developmental failure of the normal
epitympanic expansion and inadequate absorption of bony spicules by
the tympanic epithelium might result in restricted epitympanic clearance
for the head of the malleus. Fusion of the malleus to the epitympanic wall
is normally seen in a number of mammals, such as the flying fox or the fruit
bat (1).
CHAPTER 3: THE MIDDLE EAR ■ 59
Figure 36
A vertical section through the epitympanum illustrates a close proximity of
the head of the malleus to the squamous part of the temporal bone. Note
the normal thinness of the tegmen
tympani (female, age 55yr).
Figure 37
There is a fibrous attachment of the
head of the malleus with a bony spur
extending from the anterior wall of the
epitympanum (squamous temporal).
There was no documented hearing loss
(male, age 77yr).
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