in children; but in the latter alone does the atrophy extend to the
bones and cartilages, tendons, fascia, ligaments, and blood-vessels.
The osseous projections to which the muscles are attached waste; so do
the epiphyses.[52] The long bones are thinner and shorter, the foot is
shorter, and the hand is shortened in paralysis of the upper
extremity, even where this is limited to the upper arm, and the
forearm is scarcely affected (Seeligmüller).
[Footnote 52: Seeligmüller, _Centralbl. f. Chirug._, No. 29, 1879.]
In exceptional cases the limb may become even elongated from passive
extension of the ligaments of the articulation. The bones may become
soft and flexible, and break if pressure be applied.[53]
[Footnote 53: Ch. Salomon, “Des Lesions osseuses et articulaires lieés
aux Maladies du Système nerveux,” _Revue mensuelle_, No. 8, 1878.]
Atrophy of the bones stands in no fixed relation to that of the
muscles, now exceeding, now falling short of that in intensity. This
naturally progresses more slowly; still, within seven or eight months
there may be a centimeter of difference between two limbs.
In marked contrast with this profound trophic disturbance of the bones
is the intact nutrition of the skin. The absence of decubitus is
indeed an important diagnostic mark from ordinary myelitis. The
subcutaneous fat, however, wastes so completely that the skin seems to
be closely adherent to the subjacent tissues, and cannot be pinched up
into folds.
The temperature of the skin always falls; the limb is perceptibly
colder to the touch than its fellow, and is often bluish and cyanotic.
Heine has observed that the temperature diminishes gradually from the
centre to the periphery, and at the coldest point may sink to
14° R.[54] Hammond relates a case where the local temperature was 75°
in an {1125} atmosphere of 72°. The author says that exact
measurements of surface temperature should be taken with Lombard's
differential calorimeter, especially when convalescence is expected,
as then a rise of temperature, however slight, is of most favorable
augury.
[Footnote 54: _Loc. cit._, p. 16. This is not a difference of 14
degrees between the sound and paralyzed limbs, as is erroneously
quoted by Seeligmüller (_loc. cit._, p. 67).]
General factors contribute to the fall of temperature: diminished
blood-supply from shrinkage of blood-vessels, or even atrophy of a
certain number among these; loss of nerve-influence upon the oxidation
processes; loss of muscular contractions, which should attract an
afflux of blood. Among these factors the loss of nerve-supply is
probably the most important, since the others exist in cerebral
paralysis without causing the remarkable coldness characteristic of
anterior poliomyelitis.
The atrophy of the blood-vessels is not always confined to the
terminal twigs. The entire iliac artery, and even the lower part of
the aorta, have been found markedly diminished in calibre.[55] This
shrinkage is unaccompanied by any change in the walls of the
blood-vessels: it is a simple arrest of development. It strikingly
illustrates the dependence of the blood-vessels on the vascular
demands of the tissues they are destined to supply.
[Footnote 55: Charcot and Joffroy, _Archives de Phys._, 1870, case by
Séguin, _loc. cit._, p. 9.]
The changes which take place in the electrical reactions of the
paralyzed limbs rank in importance with their paralysis and their
atrophy. They serve to establish the diagnosis, to decide, to a large
extent, the prognosis, and to measure the degree of nervo-muscular
degeneration.
It is well known that the early diminution, and even entire loss, of
faradic contractility was first emphasized by Duchenne as
pathognomonic of infantile spinal paralysis. Contractility is
diminished in from three to five days after the occurrence of the
paralysis, and by the end of a week is completely lost in those
muscles in which the paralysis is to be permanent. The muscles which
recover spontaneously during the period of early regression recover
their faradic with their voluntary contractility. In others,
persistently but less profoundly paralyzed and susceptible of cure,
the faradic contractility remains simply diminished and in unequal
degrees. Progress to recovery under treatment is usually marked by
progressive increase in the faradic response; but sometimes the power
of voluntary contraction is fully regained, while the faradic response
is still permanently lessened. The loss of faradic contractility is
more complete and permanent in muscles irretrievably paralyzed by
anterior poliomyelitis than in any other disease. These laws have been
generally accepted by late observers.[56]
[Footnote 56: Simon disputes their validity, and declares that the
importance of electricity in the diagnosis of spinal paralysis may
easily be exaggerated (_Union médicale_, 7, 28, p. 942, 1879).]
In 1868, Salomon discovered that muscles in which faradic
contractility had been completely lost were nevertheless capable of
contracting under the stimulus of galvanism—that this contraction is
exaggerated, and sometimes occurs at the opening as well as at the
closing of the circuit.[57] The author remarks that the persistence of
galvanic reaction after the complete loss of faradic contractility is
completely analogous to an {1126} observation of Brucke's on muscles
poisoned by woorara,[58] where the intramuscular termination of the
nerve is paralyzed. It is to be inferred, therefore, in both cases
that the muscular contraction results from direct irritation of the
muscle, and implies the entire loss of influence from the nerve.
[Footnote 57: _Jahrb. f. Kinderheilkunde_, N. F. i., 1868. According
to Erb (_loc. cit._, p. 984) and to Ross (_loc. cit._, p. 111),
Salomon was the first to make this observation. Seguin, however,
attributes priority to Lobb (_Lond. Med. Times and Gaz._, 1863), to
Hammond (_New York Med. Journal_, 1865), and to J. Netten Radcliffe
between 1863 and 1865. These dates precede that of the publication of
Salomon's paper, but the latter seems to have been written without
knowledge of earlier observations. (See also Onimus, _Soc. de Biol._,
1878, who argues that muscle-termination of nerve is partly
destroyed.)]
[Footnote 58: “Ueber den Einfluss der Stromes dauer auf die
Elektrische Bewegung der Muskeln,” _Sitzber. d. k. Akad. d. Wissensch.
in Wien_, 1867, Bd. lxi., quoted by Salomon, _loc. cit._, p. 388.]
Erb has greatly extended these observations, and shown that the
galvanic reactions of paralyzed muscles indicate their structural
degeneration, and are identical with those observed after section of a
peripheric nerve. There are three characteristic peculiarities in the
contractions thus obtained: 1st, they are slow, tonic, long drawn out;
2d, they are more painful than in normal muscles submitted to an equal
amount of electricity; 3d, in complete degeneration the contraction
obtained at anode closure equals or exceeds in intensity that excited
by cathode closure [AnSZ = or > KSZ]. The excitability of the muscle
to the galvanic current remains increased for several months, then
gradually diminishes, and finally falls below normal. The qualitative
alterations persist somewhat longer: finally, the muscle fails
altogether to contract.
Spinal paralysis differs markedly from progressive muscular atrophy in
the absence of constant correlation between the degree of paralysis or
atrophy and of electrical changes.
The last positive symptom to be noted in the paralytic stage of
infantile paralysis is the diminution and ultimate loss of reflex
excitability. This is correlative in time and extent with the loss of
faradic contractility. This seems to be an exception to the usual
rule, which associates loss of tendon reflex with lesion of the
posterior columns or nerve-roots. This is a proof that interruption of
the reflex arc at any point suffices to abolish the tendon
phenomena.[59]
[Footnote 59: Buzzard tested the tendon reflex in the zygomaticus
major in a patient in whom the sensory branch of the fifth nerve had
been stretched, and therefore, to a certain extent insulted. The
reflex response was decidedly lower than on the opposite side
(_Lancet_, Nov. 27, 1880).]
Negative Symptoms.—The negative symptoms of atrophic paralysis are as
important for the diagnosis and pathogeny as are the positive
characters, which have now been sufficiently detailed. The absence of
decubitus or other nutritive lesions of the skin has been already
mentioned. The absence of anæsthesia, or, as a rule, of any marked
degree of hyperæsthesia, is most important as indicating immunity of
the sensory tracts in the cord. Some diffused hyperæsthesia is
sometimes noted during the febrile stage: pain is by no means rare in
adults. But in children this is altogether absent, or else slight and
transitory. On the other hand, the complete preservation of
sensibility constitutes, in children, a serious obstacle to electrical
investigation.
After subsidence of the cerebral symptoms, if any, of the initial
stage, the functions of the brain are always intact[60] and the
disposition of the children apt to be remarkably lively. The general
health is often remarkable for its vigor. The worst, because the most
neglected, cases are naturally most often seen among the poor: the
ranks of professional beggars are largely recruited from among the
victims of infantile paralysis.
[Footnote 60: Practically, it may often be of importance for the
physician to ascertain that an intellectual enfeeblement, or even
idiocy, existing at the time of examination had preceded the onset of
the paralysis by months or years.]
{1127} The chronic stage is marked by the development of a new set of
symptoms—contractions of certain muscles surrounding one or more
joints and deformed positions of the limbs. These symptoms do not
always appear. If all the muscles surrounding a joint are completely
paralyzed and extensively atrophied, and if no weight is imposed on
the limb by the action of a non-paralyzed upper segment, and if the
paralyzed segment be so supported that its own weight does not
approximate the insertion-points of muscles, and thus cause their
passive retraction, then there is no deformity, but a dangling limb, a
membre de Polichinelle.
Laborde states that contractions appeared at the earliest about two
months after the paralysis. Seeligmüller, however, has seen pes
equinus and pes calcaneus develop in four weeks. The date is partly,
at least, determined by the time at which the children try to walk or
otherwise to use the paralyzed limbs; and the deformities are very
much more marked in the lower extremities, proportioned to the much
greater weight which they are obliged to sustain.
All varieties of club-foot, and most frequently equino-varus,
knock-knees, rigid flexions at the knee and hip, cyphosis, lordosis,
and colossal scoliosis may develop as manifold consequences of
atrophic paralysis. That subluxation of the humerus and the claw-hand
may occur in the upper extremities has already been mentioned.
In Seeligmüller's 75 cases, 53, or 71 per cent., exhibited some kind
of deformity. Among these, 43, or 56 per cent., were of the foot; 6
were cases of subluxated humeri; 5, easily-reducible luxation of the
fingers.
The following table contains a summary of the deformities observed as
a consequence of atrophic paralysis. They are distinguishable from
congenital deformities dependent on altered relations of articular
surfaces through defective development[61] by being easily reducible.
This remark especially applies to paralytic club-foot:
| Equinus.
| Equino-varus (varus hardly ever alone).
Foot. | Calcaneus.
| Calcaneo-valgus.
| Valgus.
| Genu-recurvation.
Knee. | Genu-incurvation.
| Permanent flexion.
| Luxation.
Hip. | Permanent flexion.
| Permanent adduction.
| Flexion fingers or wrist (rare).
Hand. | Extension of wrist.
| Claw-hand.
Elbow. | No deformity (Seeligmüller).
Shoulder. | Subluxation humeri.
| Dorsal scoliosis.
| Lateral incurvation lumbar region.
Trunk. | Cyphosis.
| Lordosis with backward projection of shoulders.
| Lordosis without backward projection of shoulders.
[Footnote 61: _Volkmann's Handbuch_, Billroth und Pitha.]
{1128} Mechanism of Deformities.—From what has been said on the cases
in which deformities are absent it is evident that one at least of
three conditions are required for their production: the paralysis must
be unequally distributed in the muscles surrounding a joint; pressure
must be exerted by the weight of the body or traction by the weight of
the limb; effort must be made to utilize the maimed part of the limb
by means of other parts, or even by the muscles of the trunk.
The share taken by these different factors in the production of
deformities has been differently estimated by different observers. The
French surgeon Delpech was the first to explain the phenomenon on the
theory of muscular antagonism. The same theory has been most minutely
elaborated by Duchenne.[62] According to it, the intact or less
paralyzed muscles, in virtue of their tonus, constantly tend to draw
the segment of the limb on which they act in a direction opposed to
that in which it should be drawn by the paralyzed muscles. Since this
action is unantagonized, its influence persists; the insertion-points
of the contracting muscle being permanently approximated, the
nutrition of the muscle is modified: it grows shorter (adapted
atrophy). There results finally shortening and retraction of the
muscles on one side of the joint, over-stretching of those on the
other.
[Footnote 62: _De l'Électrisation localisée_, 1861.]
Duchenne used to illustrate this theory by means of a skeleton
supplied with artificial muscles, whose successive section would cause
the appearance of the corresponding deformity. Werner[63] first
protested against this theory, and the protest has been further
developed and a different theory built up through the efforts of
Hueter[64] and Volkmann.[65] The latter observes that the muscles and
ligaments surrounding a joint normally receive a large amount of the
weight falling upon its articular surfaces. Removal of this elastic
resistance exposes these surfaces to the full force of the pressure,
and thence to almost certain danger of deformity—a danger, therefore,
always incurred after paralysis of the muscles. Thus, the weight of
the body, pressing, unresisted, on the arch of the foot, is able to
displace the bones of the arch from their normal relations and
completely flatten the arch.
[Footnote 63: _Reform der Orthopædie_, 1845.]
[Footnote 64: _Gelenkkrankheiten_.]
[Footnote 65: _Sammlung klin. Vort._, No. 1.]
A position of ease is that in which the movement of the joint has been
pushed as far as possible until limited by the passive resistance of
the ligaments or the conformation of the articular surfaces. The
weight of the body must then be so placed that the line of gravity
falls on the side of the open angle, while the limiting bands stretch
across the base. Thus, a tired man sits with a curved back; the
muscles which may extend the spinal column in a straight line are
relaxed; the column falls forward until arrested by the anterior
vertebral ligaments. Thus, in standing at ease the thigh presses
against the leg, so as to form a wide angle open anteriorly. When the
quadriceps extensor is paralyzed, this position is inevitable and
exaggerated, since the force which might counteract it, contraction of
the thigh extensor, has been removed.
Formerly, the rôle of muscles in this elastic resistance was
under-estimated and that of ligaments exaggerated.
CRITICISM OF THE THEORY OF MUSCULAR ANTAGONISM.—Three considerations
have been urged in objection to the theory of muscular {1129}
antagonism: First, deformities may develop even in limbs totally
paralyzed, provided these limbs be subjected to weight and pressure.
Pes equinus, the most common form of paralytic club-foot, develops
with total paralysis of the muscles of the leg where the child does
not walk, but is carried on the arms of a nurse with its foot
dangling. The part of the foot anterior to the ankle-joint being
longer and heavier than that behind, the point falls; the tendo
Achillis is passively shortened, and by nutritive adaptation to this
position may become permanently retracted. Long persistence in this
position accustoms the dorsal surface of the bones to a less degree of
pressure than the plantar surface: as a consequence, the growth of the
bone becomes more active above, while it is arrested below; the arch
of the foot is increased until the sole is curved into a deep hollow;
and the plantar aponeurosis is correspondingly shortened.
Volkmann relates a case where this same deformity appeared without the
least paralysis, but simply from prolonged passive extension of the
feet in bed. The patient was an adult, and suffered from a severe
typhoid with a double relapse. After recovering from the fever a year
of orthopædic treatment was required to restore the feet to their
normal position.
The second objection is the absence of any proof of such constant
tonus in the muscles as may be sufficiently powerful to determine the
position of a limb. Such tonus exists in the involuntary muscles,
especially in those of the blood-vessels, but there is no evidence
that it exists in the voluntary muscles. To this Seeligmüller has
replied by admitting the objection to the theory as thus proposed, but
substituting the more plausible influence of repeated contractions on
the part of the non-paralyzed muscles. Each contraction draws the limb
in a certain direction, and there it tends to remain, because there is
nothing to antagonize the force which it has obeyed.
The third objection is that examination of individual cases not
infrequently shows displacements in directions opposed to that which
should be determined by muscular antagonism. Volkmann has especially
illustrated the latter assertion by the mechanism of genu-recurvation.
In paralysis of the quadriceps extensor of the tibia the weight of the
body is exercised, not merely from above downward, but from without
inward, falling, therefore, on the inner malleolus. It thus tends to
press the anterior part of the foot outward,[66] and a valgus finally
complicates the calcaneus. Seeligmüller, however, quotes two cases of
pes calcaneus developed in children who had never walked: in one
paralysis of the sural muscles had occurred at the age of four weeks,
and the other case was observed at the age of fourteen weeks.
Seeligmüller remarks that only early examination of the faradic
contractility of a group of paralyzed muscles can decide whether any
among them preponderate during a time sufficient to fix the limb in a
vicious position. Thus in one case of pes calcaneus he found two years
after the occurrence of the paralysis that some contractility still
persisted in the dorsal flexors, but six months later this had quite
disappeared. Had the examination then been made for the first time
when all the muscles were equally paralyzed, it would have seemed
impossible to explain the deformity by muscular antagonism.
[Footnote 66: Sayre asserts that lateral rotation cannot take place at
the ankle-joint, but at the medio-tarsal articulation. Hueter also
refers pes varus and pes valgus to the talo-tarsal articulation.]
{1130} RELATION OF WEIGHT AND MUSCULAR FORCES.—The influences of
weight and of muscular action sometimes concur, sometimes are opposed
to each other. Thus, the weight of the foot alone always tends to
produce equino-varus; it acts therefore to intensify the action of the
sural muscles when the anterior tibial are paralyzed, but to diminish
the influence of paralysis of the gastrocnemius when the foot is being
drawn into dorsal flexion. Hence one reason for the comparative rarity
of pes calcaneus.
Paralytic deformities at the hip and knee are much rarer than those of
the foot. At the hip this immunity is partly due to the relative
rarity of paralysis in the muscles surrounding the joint—still more to
the fact that the weight of the limb tends to correct excessive
flexions. These are therefore more likely to occur in children allowed
to remain in bed than in those who are encouraged to walk by means of
suitable apparatus. The use of crutches, however, favors the
development of deformity, because, since with paralysis of the
thigh- or leg-muscles pes equinus nearly always exists, the thigh is
unduly lengthened. To palliate this inconvenience the patient
instinctively flexes the knee or hip, or both, and the position tends
to become permanent.
When the flexion is rigid and extension becomes impossible, the
gastrocnemii are relaxed until they lose their power of tension, and
thence of fixing or raising the heel. Further, as by the flexion the
limb is moved in front of the body, it is necessary to project the
body forward again over the support. Hence a lordosis is developed, to
be distinguished from that caused by paralysis of the vertebral
extensors (_a_) by the rigid flexion of the thigh; (_b_) by the
facility with which the patient can extend the back as soon as he is
placed in a sitting position.
Although the quadriceps extensor is so frequently paralyzed, rigid
flexion at the knee—such as on the theory of muscular antagonism might
be expected from the action of the hamstring muscles—is very rare. As
already observed, it occurs, if at all, in neglected children allowed
to lie or sit with the leg partly flexed. In those who attempt to walk
the leg is not flexed, but forced into hyper-extension by the
following mechanism: The muscles inserted on the upper part of the
thigh swing the leg forward like a passive support. Afterward the body
bends forward over the support, and its weight, pressing from above
downward and from before backward, and pressing the articular surfaces
of the joint together, forces the head of the tibia backward until the
movement is checked by the posterior ligaments. The deformity is the
same whether the quadriceps or one or all the muscles surrounding a
joint are paralyzed (Volkmann).
DISLOCATIONS.—Dangling limbs are, however, much more frequently the
consequence of total paralysis, with extraordinary relaxation of the
ligaments of the joint permitting dislocation. Reclus[67] has
published several such cases. Verneuil has even suggested that
congenital luxation of the hip-joint always depends on an
intra-uterine spinal paralysis.[68]
[Footnote 67: _Revue mensuelle de Méd. et de Chir._, Mars, 1878.]
[Footnote 68: Quoted from Seeligmüller.]
In the upper extremities rigid contractions are much less frequent,
even in proportion to the number of paralyses. Seeligmüller has seen
five cases of reducible flexion of the fingers, and one of permanent
extension of the wrist and fingers, associated with paralysis {1131}
of all the flexors. In this case, if the arms were so suspended that
the hand hung freely, its weight gradually overcame the action of the
extensors and the fingers fell into flexion. Upon any attempt at
exertion the hyperextension was reproduced.
DEFORMITIES OF THE TRUNK.—Scoliosis will be caused when, with
unilateral paralysis of the extensors of the vertical column, the
lower part of the trunk is drawn to the non-paralyzed side, and the
upper half is bent over the paralyzed side in order to restore the
balance. In bilateral paralysis of the extensors both shoulders are
projected backward, so that a plumb-line dropped from between them
falls behind the sacrum, and lordosis is developed, although the
lumbar column is not projected forward. The same form of lordosis
occurs when the glutæi are paralyzed. When, however, the abdominal
muscles are paralyzed, the lumbar column is really projected forward,
and then a plumb-line dropped from the shoulders passes over the
sacrum.[69]
[Footnote 69: Duchenne, _loc. cit._, 1861.]