Diseases and injuries of the ear: their prevention and cure

Front matter

Uv^^

PRACTICAL LESSONS IN NURSING.

12mo. Extra Glotli. $1.00 each.

Preface

In the following pages the author has endeavored to present the important subject of ^* Diseases and Injuries of the Ear/^ in a form free from technical terms, so that it may be understood by any one. This plain description of ear-diseases, it is hoped, will enable many to avoid them by care, or, if contracted, will aid in recognizing their nature and thus prevent experimental and erroneous forms of treatment so much in vogue, and which usually do more harm than good. The aim also has been to show the inexpert what to avoid in the treatment of ear-diseases, rather than what they may try to do for their relief. In this way it is believed the general reader can be best warned against error in treatment, and the hearing saved.

If this little book can show how to take care of the ears and avoid disease in them, or, if they are diseased, how to escape the evils of improper treatment, the author's object will be fully attained.

127 South Eighteenth Street, Philadelphia.

PART I. Structure and Function of the Bar

CHAPTEE I. p^^^

The External Ear 9

The Middle Ear 13

The Internal Ear 20

CHAPTER II. Sound 24

Hearing 25

F^ART II.

Common Diseases and Injuries of the Bar : their Prevention and Cure.

CHAPTEE I.

Diseases and Injuries of the External Ear ... 35

CHAPTER II.

Diseases and Injuries of the Middle Ear .... 72

CHAPTER III. Diseases and Injuries of the Internal Ear: the

Deaf and Dumb 132

1* 5

CONTENTS.

F>ART III.

Aural Hygiene of the Deaf.

Chapter I. Pagb

Aural Hygiene and Education oe Partially Deae

Children 142

CHAPTER 11.

Aural Hygiene and Education op the Deaf and

Dumb 147

DISEASES

AND

INJURIES OF THE EAR;

THEIR PRETENTION AND CURE.

STRUCTURE AND FUNCTION OF THE EAR.

CHAPTER I.

THE DIVISIONS OF THE EAR.

The organ of hearing, or the ear, is the most complex of all the organs of special sense. For the sake of convenience in speaking and writing of the ear^ it IS divided into three parts, — viz., the external, the middle^ and the internal ear.

The external ear is composed of the auricle, commonly termed the ear, and the canal leading from it to the drum (Fig. I., 14). This canal is termed the external auditory canal. It is about one inch and a quarter long. The auricle, the auditory canal, and the drum-membrane are the only parts of the ear visible from without. The other parts of the ear are situated beyond the drum-membrane, and are, of course, invisible. .

DISEASES AND INJURIES OF THE EAR.

Fig. I.

Si

3 4 5

Diagram of the entire Auditory Apparatus of Man; right side; nearly natural dimensions. (From "Hearing, and How to keep it," by C. H. Burnett, ^[.D.) The front part of the auditory canal, the front half of the drum-membrane, and part of the Eustachian tube are supposed to be removed. 1, the side of the temple-bone cut through ; 2, outer surface of the temple-bone ; 3, upper wall of bony portion of hearing canal ; 4, ligament holding the hammer-bone to the roof of the drum -cavity ; 5, roof and upper part of the drum-cavity ; 6, semicircular canals ; 7, anvil-bone (incus) ; 8, hammer-bone {malleus); 9, stirrup-bone {stapes); 10, cochlea (snail-shell); 11, drum-membrane cut across and looked at sideways; 12, isthmus of the Eustacliian tube, in the naso-pharynx ; 13, mouth of the Eustachian tube behind the nose; 14, the auditory or hearing canal; 15, lower wall of bony portion of the auditory canal; 16, lower wall of the cartilaginous part of the auditory canal at its junction with the bony portion ; 17, wax-glands ; 18, the lobule ; 19, upper cartilaginous wall of the auditory canal ; 20, the mouth of the auditory canal ; 21, the antitragus.

The middle ear is that part lying between the drum-head, or drum-membrane, and the internal ear (Fig. I., 5). In this cavity of the middle ear lie the three ossicles of hearing, or auditory bonelets (Fig. I., 7, 8, 9). In the internal ear is the nerve of hearing. This part lies entirely in bone^ and is a small space. It is near the brain, in the petrous or stony bone, so called from its great hardness (Fig. I., 6, 10). The anatomical knowledge of the ear is difficult, but it seems best to give these few guiding facts as to the divisions of the ear, in order to understand what is said of its diseases and injuries. The chief object of this little work is to guide the reader in the prevention and cure of diseases and injuries of the ear. What is here set forth will certainly therefore be better understood if the reader has some idea of the general structure and function of the different parts of the organ of hearing.

The External Eae. — The outer part of the external ear is the auricle. This is a cartilaginous shell covered with delicate skin. The latter fits into every groove, elevation, and depression of this cup, except at its lowest part. Here there is found simply a cushion of fat covered with skin. To this so-called lobule (Fig. I., 18) ear-rings are often hooked. Numerous blood-vessels, nerves, and lymphatics run through the auricle. It is held fast to the side of the head by ligaments and delicate muscles in man. In the lower animals these muscles are strong and endowed with the ability to move the auricle. The skin of the auricle is abundantly supplied with sebaceous and perspiratory glands, like the rest of the skin of the body. The sebaceous glands are most numerous in the cup of the auricle, where it passes into the mouth of the auditory canal (Fig. I., 17). There is downy hair on the auricle. The long hair on the bulbous projection at the mouth of the ear-canal is a protection against cold air, insects, etc. The sweatglands of the auricle are most numerous on the back of it, — an important fact to remember in the nursing of infants; for if their auricles are pushed against their heads and firmly held there, maceration and inflammation of the skin may ensue.

The Auditory Canal. — The auditory canal may be considered the inward continuation of the auricle. It is a canal one and a quarter inches in length by about a quarter of an inch in width, and ends at the drum-membrane (Fig. I., 11). The canal is a little narrower half-way down than it is at either end. Its outer third is composed of cartilage, while its inner two-thirds is of bone. The skin which lines this canal possesses all the elements of true skin. At its outer part, near the junction of the cartilaginous with the osseous part, lie the wax-glands (Fig. I., 17). These are fifteen hundred in number, and secrete the very useful matter called ear-wax. It will be further shown that this substance is most important to the welfare of the ear.

The Drum-membrane. — The drum-head, or membrana tympani, is the air-tight partition at the bottom of the auditory canal, between the external and the middle ear (Fig. I., 11). This is the part popularly called the ^Mrum.^^ This is not an accurate terra, as it is really only the outer wall of the drum-cavity or middle ear, and might therefore be called the " drum-head." The drum-head is nearly circular (Fig. II.), about a quarter of an inch in diameter, and about ^^ of an inch thick. The drum-membrane is composed of three layers, — the outer one being of skin, a continuation of the delicate skin which lines the auditory canal. The middle layer is of fibrous tissue, and the inner layer is

THE DIVISIONS OF THE EAR.

of mucous membrane, continuous with that which lines the middle ear or drum-cavity.

In the central line of this drum-membrane is an opaque, white ridge, running from above downward and backward (Fig. II., 5). When the drum is in-

Outer Surface of the Drum-membrane. Magnified 33^ times. (Politzer.) 1, 1, the flaccid part of the dnim-membrane; 2, the short process of the hammer-bone ; 3, back fold of the drum-membrane ; 4, the long limb of the anvil-bone, shining through the membrane ; 5, 5, the true membrana tympani, or membrana vibrans ; 6. 6, 6, 6, inner end of bony canal, forming frame for drum-membrane ; 7, the pyramid of light ; 8, lower part of the hammer ; 9, the front fold of the drum-membrane.

spected, this white ridge is the first glimpse the examiner gets of the chain of auditory bouelets already alluded to. This chain of little bones connects the drum-membrane with the portion of the inner ear where the nerve of hearing lies (Fig. I., 7, 8, 9). The white ridge just mentioned is the so-called handle of the hammer, or malleus, the largest of the three auditory bonelets.

This bone is all the more likely to move with every motion of the drum-membrane, because its handle is firmly embedded in the dense middle, fibrous layer of the membrana tympani. When the mechanism of the auditory bones, as a whole, is considered, the further advantage of this intimate connection between the hammer-handle and the drum-head will be shown. At the bottom of the auditory canal we find the drum-membrane fixed in a bony ring of its own, about one inch and a quarter from the opening of the external canal in the auricle. Several features at once attract the eye of the observer when a normal drum-membrane is looked at, in its proper position. Its shape is nearly circular; its color is a delicate bluish pearl, except at the white ridge of the handle of the hammer-bone. There is further noticed the peculiar tint obtained by stretching a transparent membrane over a dark cavity. This is due to the fact that the light in the drum-cavity passes first through the drum-membrane from the outside. It will also be observed that the surface of the drum is smooth and lustrous. This lustre is so great at the lower and front part of the drum that at this point, between the circumference of the membrane and the lower end of the hammer-handle, there is a shining triangular reflection of light. This is called the '' pyramid,^^ or "cone of light,^^ and can be seen in any normal ear (Fig. II., 7). There is a prominent point at the upper end of the handle of the hammer, called its short process (Fig. II., 2). This point plays an important part in plotting out the drum-membrane and in getting one's bearings when examining the ear. The short process looks not unlike a small, whitish pimple.

It is situated in the upper periphery of the drum-membrane, at the upper end of the aforesaid white ridge. Two prominent ridges pass from it, one backward, the other forward, to the periphery of the drum-membrane, and are called the folds of the membrane (Fig. II., 3, 9). They serve as the upper boundary of the membrane proper, the so-called vibrating membrane (membrana vibrans). Above these folds is a part of the drum-membrane in a triangular spot, without any fibrous tissue. This is called the flaccid membrane, or membrana flaccida (Fig. II., 1? 1). The neck and head of the hammer-bone lie directly behind this last-named part of the membrane.

These parts of the hammer bonelet are never visible, however, from without when the ear is in a healthy state. The leverage-line of the hammer lies in the line of these folds. The lower arm of the lever is represented by the handle of the hammer, below the folds, and the short arm, by the neck and head of the same, above the folds. In every vibration of the membrane and bonelets, the malleus, or hammer, swings with a minute excursion about this axis-line, marked by the line of the folds of the membrane.

The Middle Ear. — The middle ear is the seat of most of the diseases of the ear. Its structure, therefore, demands a brief consideration. It is composed of the drum-cavity, and two important adjuncts, — viz., the mastoid cells behind, and the Eustachian tube, connecting the ear with the nose, in front. The drum-cavity is the most complicated and delicate of the three portions just named, and is most liable to disease (Fig. I., 4, 5).

Drum-cavity, — This cavity may be described as bounded by four walls, a roof, and a floor. The walls are named the front, the back, the inner, and the outer. The three auditory bonelets are the most important contents of this chamber. It is, however, lined with a most sensitive mucous membrane, which when inflamed gives rise to excruciating pain. This important cavity is about half an inch in height and width, and from a twelfth to a sixth of an inch deep, measured from without inward, and lies just beyond the drum-membrane. The mucous membrane which lines it is a continuation of that of the nose and upper part of the throat. This cavity is the true drum, and to it alone the name of drum should be applied. When the name of drum is given to the drum-membrane or drum-head, great confusion arises.

Auditory Bonelets, — The ossicles of hearing, or auditory bonelets, are three in number, — the hammer, or malleus^ the anvil, or incus, and the stirrup, or stapes, named from the fancied resemblance in shape to these implements (Fig. III.). They form the so-called "chain of bones'^ of the ear. Starting from without, the first bonelet is the malleus (Fig. III., 1, 2, 3), the second is the anvil (Fig. III., 4, 5), and the third, the innermost one, is the stirrup (Fig. III., 6). The first-named is the largest ; the last-named is the smallest ; in fact, it is the smallest bone in the body.

The hammer is divided into a head, a neck, and a handle. Its length is about a quarter of an inch, one half of which is formed by the handle. The head is about one-eighth of an inch thick. The handle of this bonelet is set into the membrana tympani, and holds it taut. Besides this support, the hammer is held firmly in position by ligaments which fasten it to the roof and outer wall of the drum-cavity (Fig. I., 4).

Fig. III.

The three little bones of the ear, from the right side, in natural connection, seen from within. Magnified about four times. (Henle.) 1, head of the hammer ; 2, long process of hammer, not found in adults ; 2 a, the short process of the hammer ; 3, the handle {manubrium) of the hammer-bone ; 4, the long limb of the anvil-bone ; 5, its short limb ; 6, the stirrup-bone.

As we pass inward, next in order comes the anvil. It is divided into a body and two limbs, the horizontal or short one, and the descending or long one. This bonelet, like the hammer, is held to the upper and posterior wall of the drum-cavity by ligaments, and is jointed to the hammer on the outside of its body, and to the stirrup by the tip of its long limb (Fig. III., 4). The joint between the hammer and the anvil has the peculiarity of unlocking or loosening if the hammer is pulled outward, but if the handle is pushed inward, about the axis-line already described (p. 13), this joint between the hammer and the anvil is only the more firmly locked, and the anvil is carried inward towards the inner ear. In fact^ this form of motion occurs with every impression of sound upon the drum and the nerve of hearing. This function in this joint will be found very important when the mechanism of sound and hearing is considered. The action in this joint has been likened to some watch-keys which wind the watch when turned in a certain direction, but when turned in the opposite way unlock the barrel and fail to wind the watch.

The stirrup is the innermost of the three bones we are considering (Fig. III., 6). It is also the smallest bone in the body, its entire length being one-eighth of an inch. It is divided into a head, a neck, two legs, and a foot-plate. At the junction of the two legs is found the head, in the form of a cup-shaped button. It is designed to receive a knob-like projection on the end of the anviPs long limb. The two legs of the stirrup are made lighter, without being weakened, by a furrowing on their inner surfaces. The foot-plate is ovoid or slightly kidney-shaped, and fits accurately into the oval window of the labyrinth, in the inner wall of the drum-cavity (Fig. I., 9). In this window it is hermetically held by a fibrous packing, as will be further shown. The connection is thus made between the outer ear and the drum-head, on one side, and the labyrinth and the nerve of hearing, on the other. This entire chain of auditory bones moves in and out as a whole, performing a pendulum-like motion about the axis-line in the folds, already described (p. 13). This kind of oscillation, to and fro, on the part of the drum-head and the chain of auditory bones, causes the foot-plate of the stirrup to play backward and forward in the most minute excursions. This movement of the stirrup, in turn, sets the water in the labyrinth in motion, and impresses the auditory nerve, producing thereby hearing.

Boundaries of the Drum-cavity, — The dividing partition between the drum and the brain is the so-called roof of the drum (Fig. I., 5). This boundary is very thin, and in some individuals has chinks in it. On this account an inflammation in the drum may pass into the brain and prove fatal.

The front wall of the drum is nearest the throat or nose, and has in it the opening for the reception of the Eustachian tube (Fig. I., 11, 12). On its upper and inner part there is a canal, through which a little muscle passes called the ^^ stretcher of the drum" {tensor tympani), on its way across the drum-cavity, to be inserted into the handle of the hammer on its inner and upper part. This muscle is an offshoot from the muscles of the throat and Eustachian tube, and hence sympathizes with their diseases.

The back wall, like the front, is narrow. It too contains an opening, which communicates with the mastoid cavity and its cells. The topography of the inner and outer walls of the drum or tympanum are more intricate. The outer wall of the drum-cavity is composed mainly of the drum-head. The limit of this wall is the bony ring in which the drum-membrane is stretched (Fig. I., 11). "We have already stated that the hammer-bonelet is closely connected with this wall by its handle (p. 14). An important nerve passes across the inner surface of this wall, near the upper boundary of the drum-membrane. Around this nerve a fold of b 2* mucous membrane passes, and, standing off a little from the surface of the drum-membrane, forms with it a crease, or groove, opening downward. There are two of these so-called pouches of the drum-membrane, one in front of, and the other behind, the hammer.

The inner wall of the drum demands close examination. Here we find on the posterior portion the promontory, caused by the outward projection, towards the drum, of the lower turn of the cochlea, yet to be described. This can often be seen through the drum-membrane, as a pale-yellowish spot. Sometimes the membrane touches the promontory, and in some cases adheres to the inner wall at this point. Above the promontory is the oval window, into which fits the foot-plate of the stirrup-bone (Fig. I., 9). Behind and below the promontory is the round window. A little muscle runs from the head of the stirrup backward to its origin in a hollow pyramid of bone in this inner wall.

The little oval window is about ^ of an inch in its longest diameter and about ^ of an inch in its shortest. The diameter of the round window is about ^ of an inch.

Behind the oval window a ridge begins, which marks the course of a bony canal, conveying the facial nerve through the drum to the face. This will account for the fact that inflammation in the ear sometimes produces paralysis of the corresponding side of the face. The ^oor of the drum-cavity is only a narrow groove ; beneath it runs the jugular vein on its way to the lower part of the neck. This accounts for the fact that the movements of the blood in this vein sometimes cause abnormal sounds in the ears.

THE DIVISIONS OF THE EAR. I9

Eustaehian Tube, — This tube, or canal, forms the only aerial communication between the nose and the ear (Fig. IV.)- It opens near the posterior nostril in the upper part of the throat, behind and above the palate. Its course is upward, outward, and backward towards the drum. In the pharynx or upper throat the opening of this tube is wide (Fig. I., 13). It then

Transverse section through the Eustachian tube. Magnified about four times. (Henle.) 1, cartilaginous upper and back wall; 2, the cavity of the tube proper; 3, the front wall composed chiefly of muscle ; 4, the hook-shaped part of the upper wall, curving forward to join the muscular wall. This hook-shaped part moves with the muscles in every act of swallowing, and aids in widening the cavity, 2, through which air passes to the inside of the drum.

narrows to what is called the isthmus (Fig. I., 12), from which it widens again to the tympanic cavity. The entire length of this tube is a little more than an inch. Two-thirds of the tube is cartilage ; the other third is bone. It is lined with mucous membrane, continuous with that of the throat, nose, and drum-cavity. Hence diseases pass readily from the nose and throat to the ear.

This tube is provided with muscles which arise from the palate and are attached to its cartilaginous part. When these are moved in swallowing they draw the cartilaginous walls of the Eustachian tube apart and allow air to enter the drum-cavity. This is necessary for the healthy action of the ear. If it is deprived of air for any length of time, deafness and earache set in.

Mastoid Cells. — The last division of the middle ear which claims attention is the mastoid portion, with its peculiar cells. This is located behind the ear, in a rounded prominence easily felt by all. It is filled with a number of small bony cells, hollow, containing air, and lined by mucous membrane. One large one is situated at the opening into the drum-cavity. This is called the antrum^ or cave. It is often the seat of disease, which we shall consider later.

The Internal Ear. — The internal ear is also called the labyrinth. It is composed of the vestibule in the middle, the cochlea in front, and the semicircular canals behind (Fig. I., 6, 10). It is a hollow bony cavity, containing soft tissues of a similar shape, also hollow, and receives the expansion of the auditory nerve. The oval window, already alluded to (p. 18), is in the vestibule. Through this window by means of the foot-plate of the stirrup-bone (Fig. I., 9) pass the waves of sound in normal hearing, on the way to the auditory nerve. The vestibule-cavity is pear-shape. It is about \ of an inch wide from within outward, and a little more than -^ of an inch measured from front to back. Its four walls run together where the cochlea begins. This latter cavity, as its name implies, is shaped like a snail-shell. It is, in fact, a bony canal wound two and a half times about a bony pillow (Fig. I., 10). This canal of the cochlea is partly divided longitudinally by a bony shelf, which partition is completed by a membrane. Thus we find the cochlear canal divided into two smaller canals, or stairways as they are termed. They are joined together at the top of the shell, at the cupola.

The canal of the cochlea being divided into two passage-ways, one can imagine one's self entering the upper passage from the vestibule, and emerging at last by the lower one at the round window. This latter window is closed by a membrane, which shuts it off from the drum-cavity.

When the fluid which fills the vestibule and entire labyrinth is pressed upon by the foot-plate of the stirrup, in the oval window, it finds relief at the round window by the yielding of the aforesaid membrane.

The semicircular canals, three in number, communicate with the back part of the vestibule (see Fig. I., 6). Thus we complete the sketch of the bony labyrinth. This is a hollow cavity, and, in its normal condition, filled with water. In this are supported delicate soft structures similar in outline and shape to the bony case containing them, and hence called the membranous labyrinth. They may be considered hollow casts of the bony labyrinth. They contain in their soft and delicate cavities the terminal nerve-branches of the acoustic nerve.

Membranous Labyrinth, — Within the vestibule, already described, are found two little sacs, the round and the elliptic, which may be regarded as the central part of the membranous labyrinth. The elliptic is the larger, and with it unite the membranous semicircular canals. It is joined to the round sac by means of a V-shaped canal. The round sac unites with the cochlea. Hence the membranous labyrinth, like the

A diagrammatic representation of Corti's organ, the ultimate distribution of the auditory nerve in the internal ear. Magnified between 300-400 times. 1, the base of the inner hairy cells : auditory nerve passing between them ; 2, section of a blood-vessel; 3 and 5, the basilar membrane, uniting the edge of the bony shelf at 1 with the outer wall of the cochlea at 6, thus dividing the cochlear canal into A, the vestibular scala, and C, the tympanic scala ; 8, the outer pillar of Corti leaning against 9, the inner pillar forming Corti's arch ; 4, outer hairy cells, receiving nerve-filaments from 14, the nerve of hearing; 7, upper ends of haired cells where the acoustic hairs are found ; 10, upper ends of inner haired cells ; 11, Corti's membrane ; 12, upper lip of bony shelf: the nerve of hearing, 14, runs through lower part of this shelf, emerging at 1, in the lower lip of bone. Corti's organ may be said to lie between the lines 5 and 12.

bony case containing it, is in reality one cavity. It lies in water, and is also filled with it. This labyrinth-water is part of the natural water of the brain and skull-cavity. The vestibular branch of the auditory nerve supplies branches to all soft parts in the vestibule and membranous semicircular canals, and the cochlear nerve supplies the soft tissues in the cochlea.

It may be of interest to the reader to trace the course of the nerve of hearing in its distribution to the cochlea.

Cochlear Nerve and CorWs Organ. — The cochlear nerve, after entering the base of the bony pillar around which the cochlear canal is twined, emerges on the bony shelf of the canal, and is spread out over the latter, like a fringe. Let us trace one filament of this nerve on its way over this shelf and to its terminus, the so-called organ of Corti. The latter is simply a support, and not a percipient organ. It consists of two pillars placed on the membranous partition between the two cochlear stairways (see Fig. Y., B, C). These pillars lean towards each other and are united above, forming a so-called arch of Corti. A delicate net-work, running parallel to the membranous partition above named, is supported by this arch. In this net-work are held a series of cells or disks, with fine hairs on their upper ends. To these cells, named hair-cells, the nerve passes and is attached, as its ultimate destination (see Fig. V., 7, 14).

There are three thousand of these organs, or arches of Corti, in the human ear

CHAPTER 11.

PHYSIOLOGY OF THE EAR.

Sound.

Sound is motion imparted to the auditory nerve. The motion productive of sound is usually conveyed by undulations in the air. A sounding body communicates shocks to the surrounding atmosphere, which pass by waves of undulation, as they are called, on all sides which are free, as the waves ripple the surface of water after it is disturbed by a pebble thrown into it. Sound moves at the rate of 1090 feet per second in air at the freezing-point. The velocity increases two feet per second for each increment of 2° Centigrade, in temperature. Let us assume that water represents the atmosphere, the pebble the source of sound in the vibrating body, the ripples on the surface of the pond the waves of sound in the air, and then the shore of the pool will represent the ear, or the point where sound is received. The perception by the ear of these motions or vibrations in the atmosphere is hearing.

Intensity of sound depends on the breadth of these waves ; pitch depends upon their number in a second ; and quality (clang-tint, or timbre) depends upon the peculiarity and manner of the occurrence of the sound. Partial tones, so called, compose a sound, just as ordinary light is composed of several colors. The difference in sounds depends upon the number and strength of these partial tones. Thus it is that one voice differs from another. The first partial tone is called the fundamental note ; the others are called the harmonics or '' over-tones,^'