Chapter IV: Section I: Contractions of the Fingers (2)

“_Hammer finger_” (Fig. 6) is not a rare complaint, although much less familiar, possibly because much less troublesome, than hammer toe. It may be defined as a permanent flexure of one or more digits, nearly always at the first or second inter-phalangeal joint, and unassociated with inflammatory or degenerative disease in the articular structures, or with any evidence of paralytic or spastic phenomena in the muscles. It is strictly limited in onset to the developmental period, and may manifest itself at any time between birth and adult life, possibly even before birth in some instances. It is more common in girls than in boys. The digit most frequently attacked is the little finger, and the proximal inter-phalangeal joint is more often affected than the distal joint. It is usually symmetrical. The contraction is slow, progressive, and painless, and becomes arrested spontaneously at any degree of flexion, but seldom goes beyond an angle of 90°. The joint cannot be extended by any ordinary force except in the earliest stage, and even then the bent position is immediately resumed after the cessation of the effort. Flexion, on the other hand, is complete and of fair power. No alteration is produced in the deformity by flexion of the wrist, a fact which proves that the main obstacle to extension does not lie in the tendons. There are no contracted fascial bands, and, as a rule, the skin is normal, but occasionally a small longitudinal fold may be present in the angle of flexion. In rare instances the resistance to extension is capable of yielding suddenly with a spring-like action, and a similar movement recurs as the joint is replaced in the position of flexion. These cases are usually classed with the condition known as “trigger finger.” The contraction also occurs in the metacarpo-phalangeal joint, but very rarely attains a degree marked enough to attract the attention of patient or surgeon. In 800 children examined at the Central District School at Hanwell by Dr. Litteljohn and myself, this affection was found seven times—five times in girls, twice in boys, the ages of the subjects ranging between eight and fourteen. In all these the deformity was confined to the little finger, and in six cases it was bilateral. The proximal inter-phalangeal joint was affected in ten, and the distal joint in three of the thirteen digits. The angle of flexion measured from the prolonged metacarpal axis, ranged between 20° and 80° in the different cases. A contraction of less than 20° was frequent, but the deformity was so slight that the cases were not recorded as pathological. Besides these examples, I have met with several cases in adult women, in whom the defect is said to have originated in early childhood. The little finger was affected in all, but in one the ring finger, and in another the ring and middle fingers were also involved. Only the last was unilateral. The following case may serve as a type of the more troublesome forms:

G. B., a domestic servant, aged twenty-two, was admitted into
St. Thomas’s Hospital in June 1889, with contraction of the
third, fourth, and fifth fingers of the right hand at the first
inter-phalangeal joints. The patient, a strong, healthy girl,
quite free from neurotic tendencies, stated that her little and
ring fingers had been contracted from early childhood, and that
the condition had increased slowly but progressively to the
present time. The middle finger became similarly affected about
five months before admission. She had never suffered from pain,
and the parts had been free from all sign of inflammation;
the deformity, however, caused very great inconvenience in
her occupation. Two months before admission an attempt had
been made to relieve the flexion of the little finger by
subcutaneous section of the fascia, with the result of inducing
a traumatic contraction of the metacarpo-phalangeal joint.
The family history was negative. On examination the little
finger was found to be flexed at an angle of 90° at the first
inter-phalangeal joint, and the metacarpo-phalangeal joint was
bent at an angle of 120° by cicatricial contraction of the skin
and subcutaneous tissue (the result of the operation alluded
to). The ring finger was flexed at the first inter-phalangeal
joint to about 110°, and the middle finger at the corresponding
articulation to about 150°. In the case of the inter-phalangeal
joints, the movements in the direction of flexion were quite
free and of normal power, but extension was strongly resisted
by ligamentous tension at the points named. No increase in the
range of movement was gained by flexion of the wrist. A first
operation was undertaken for the relief of the cicatricial
contraction at the proximal joint of the little finger. The
tense integumental band was divided, and after straightening
the joint a flap was dissected from the ulnar side of the
digit opposite the point of incision and twisted into the gap.
(Fig. 4.) The wound united by first intention, and the result
was permanent. A week later an operation was performed upon
the first inter-phalangeal articulation of the same finger.
The lateral ligaments were divided subcutaneously near their
proximal attachment, and it was found that the joint could
then be straightened by the use of moderate force; but on the
discontinuance of the extension the contraction was reproduced
by the elastic tension of the flexor, except during flexion of
the wrist. The hand was placed upon a splint. The patient, who
did not bear restraint well, left the hospital, and has since
been lost sight of.

There is little doubt that in this case the primary contraction was due to imperfect evolution of the ligaments, and that the shortening of the tendons was secondary. The reason for accepting this order of phenomena is that a pure myogenic contraction does not readily lead to changes in the joint structures, because the articulations are capable of full extension while the flexor tendons are relaxed by bending the wrist, and hence the limitation of movement is not constant. (See Case recorded on page 58.) On the other hand, in a permanent contraction of a finger-joint occurring during the period of active growth the flexors are never stretched to their full extent, and consequently do not undergo their normal longitudinal development; but should such a contraction originate in an adult the case is different, as muscle and tendon show very little disposition to undergo active involution in the direction of their length after their complete development is attained; and hence after division of the abnormal bands in true Dupuytren’s disease the tendons do not impede the complete extension of the digit. This law, that joint contractions commencing in youth lead to shortness of muscle tendon, while those beginning in adult life do not, is worthy of the attention of the surgeon.

_Pathology._—The affection is of some pathological importance, because it affords a simple test case by which many other questions of larger moment may be decided. It has been demonstrated that the permanent obstacle to extension of the contracted joint is to be found in the ligaments, there is no evidence of either muscular or nervous impairment or of any inflammatory changes in or about the joint, the process of contraction is slow and painless, and the condition always originates and progresses to its maximum during the term of active growth. In order to understand the significance of the complaint, it is necessary to dwell upon some facts in digital anatomy and physiology that have not received the consideration they deserve. If we examine a number of hands, it will be found that there is a remarkable wide physiological variation in the range of movement at the phalangeal articulations in different individuals, and it requires but a small departure outside the physiological limits of variation to constitute the pathological deformity under consideration. The results of my own observations are as follows: (1) At each of the digital joints the distal bone, starting from the position of extreme flexion, passes through a variable number of degrees before it reaches the point at which it is arrested by tension of the ligaments. In the metacarpo-phalangeal joint the angle formed between the two bones during extreme flexion is usually about 80°, and the entire extending movement from this point may be represented in the healthy hand by any number of degrees between 90 and 190. That is, in one person the motion is arrested a little before the axis of the phalanx reaches a line with that of the metacarpal bone; in another it may be possible to continue the extension until the two bones form an angle with a dorsal opening of 90°. At the first inter-phalangeal joint there is a similar but less extensive variation. The extreme flexion angle is 60° or 70°, and the full extension may be checked as soon as the axes of the two bones are in the same line (frequently a little before this point is reached), or may be carried on 30° beyond. In the distal joint the flexion angle is about 80°, and extension may be checked when the two bones are in the same line, or may be capable of continuation for 40° or more. In the thumb the range of movement at the metacarpo-phalangeal joint varies from 80° to 170°, and at the inter-phalangeal joint from 90° to 120°, in different persons—i.e., the physiological variation in the two articulations is 90° and 30° respectively. The diagram (Fig. 7) may help to render this clear. It is not only in different individuals that such variations are apparent, but the fingers of the same hand and corresponding fingers in opposite hands may differ from each other to a marked degree in range of extension. The super-extension is usually greatest in childhood, and undergoes great diminution as adult life is approached, although in many cases it is persistent; as a rule, however, the limitation is in direct proportion to the strength of the hand, and is hence nearly always greater in the left hand than in the right. These peculiarities are matters of common observation, and popular expressions have ever been coined to represent the extremes in the range of variation. Thus a person who is able to bend his joints backwards to a conspicuous degree is said to be “double-jointed,” and one who cannot extend them beyond the straight line is called “stiff-jointed”; and it is well known that “double-jointedness” and “stiff-jointedness” run in families, and in some cases may be traced through several generations. In the author, for example, the metacarpo-phalangeal joints of the index and middle fingers of the right hand are “stiff,” while those of the left are capable of a super-extension of 45° beyond the metacarpal axis; and precisely the same condition was present in his father, and has been transmitted to his son.

A. Skeleton of finger with lateral ligaments; 1. Metacarpal bone; 1_a_. Anterior fibres of lateral ligament blending with glenoid plate; 2. Metacarpal phalanx; extension checked by short anterior fibres of lateral ligament (1_a_) at line of metacarpal axis; 2_a_. Super-extension permitted when 1_a_ long; 3 and 3_a_. Middle phalanx under conditions similar to 2 and 2_a_; 4 and 4_a_. Ungual phalanx.—B. Hammer finger; extension at first inter-phalangeal joint arrested by imperfect longitudinal development of anterior fibres of lateral ligament.—C. Palmar aspect of first inter-phalangeal joint (left middle finger); 1. Metacarpal phalanx; 2. Middle phalanx; 3. Anterior fibres of lateral ligament decussating with those of the opposite side; 4. Glenoid plate.]

It may be of advantage to describe the articular structures of one of the finger-joints somewhat in detail. The capsule of an inter-phalangeal joint is formed on the dorsal aspect by the expansion of the extensor tendon, reinforced by the transverse fibres (the _ligamenta dorsalia_ of Henle), which bind the tendon to the bone and lateral ligaments; on the palmar surface of the articulation is a glenoid plate of fibro-cartilage firmly attached to the anterior border of the distal bone, but very feebly connected with the neck of the proximal bone, and fused intimately with the anterior fibres of the lateral ligaments; lastly, at the sides of the joints are the radial and ulnar lateral ligaments, the attachment of which it is important to study closely, as they are often imperfectly described in anatomical text-books. The fibres of each lateral ligament are attached above to a little tubercle at the side of the head of the first phalanx, and from this point they radiate in a fan-like manner—the more posterior passing to the side of the base of the second phalanx, the rest blending with the glenoid plate, and through the intermediation of this are connected with the anterior border of the base of the distal bone, decussating to some extent with fibres of the opposite ligament. (Fig. 7, C.) The strongest part of the glenoid plate, in fact, is made up of these ligamentous fibres; and it is these which, relaxed in flexion, become progressively more and more stretched during extension, and at length by their tension bring the movement to a close, but, as already shown, the point at which the maximum tension is reached varies to a large extent in different individuals.

The physiological variations in the range of movements are thus to be explained by variations in the relative length of the anterior fibres of the lateral ligaments. The ideal constitution of a joint depends upon the existence of a certain ratio between the growth of bone and that of ligament. Should the ligaments grow in excess, their redundant length will permit great super-extension, and may even cease to check the movement; but if the bone grow relatively faster than the ligaments, the anterior portion of the latter will the sooner become tense during extension, and where this disproportion is exceptionally great the motion may be checked before it attains physiological completeness, the result being a “hammer finger.” Irregularities of development are most likely to occur in those joints which, for one or other reason, have the least functional activity. In the hand the little finger is much less powerful than its fellows; and in association with this it may often be noticed that the fourth tendon of the flexor sublimis is reduced to a mere thread; in the foot the same thing is observed in the corresponding digit, but in a more marked degree, and it is the degenerate little toe which is most liable to the “hammer deformity.”

We may then define hammer finger as the result of a developmental irregularity of the first or second inter-phalangeal joint (rarely of the metacarpo-phalangeal joint) by which the anterior fibres of the lateral ligaments become prematurely tense during extension, and so check that movement before it attains its normal physiological limit. It is precisely analogous to hammer toe; but it is of less frequency than the latter affection, because while civilisation sedulously cultivates the freedom and precision of action in the fingers, it devises foot-coverings to repress the natural play of the toes. The tendency to the deformity may be transmitted by descent through an indefinite number of generations.

_Diagnosis._—Spurious hammer finger, like false hammer toe, may occur from—(1) articular lesions due to rheumatism, rheumatoid arthritis, gout, tuberculosis, and inflammations of traumatic origin; or (2) from interference with the muscular functions by paralysis of the extensors or by spastic contraction of the flexors. In the first group the joint will be found in a more or less complete state of ankylosis, movements in all directions being impeded. In the second group the articulation, although contracted, is freely mobile under passive force, unless, as in some congenital paralyses, irregularities of development in the articulations be superadded.

_Treatment._—The treatment of hammer finger is a far less simple problem than that of hammer toe, because in the toe the sacrifice of the movement of the affected articulation does not sensibly impair the utility of the digit, while in the fingers an ankylosis of the first inter-phalangeal joint in the position of either flexion or extension would be even more inconvenient than the ligamentous contraction. The measures available are (1) passive movement; (2) subcutaneous section of lateral ligaments, with or without tendon lengthening; and (3) amputation. In the milder cases a persevering use of passive motion will in time effect a cure; but when the contraction has reached an advanced degree it may be impossible to make an impression by this means. We may then divide the lateral ligaments, and keep the fingers straight by means of an extension splint while the tendons are relaxed by flexion of the wrist, trusting to subsequent massage and passive motion, or, failing this, to tendon lengthening (by a process to be described later), to overcome the resistance of the shortened muscles. Section of tendons within the theca is useless, because no uniting material is thrown out between the divided ends. As a last resource, amputation may be demanded to remove a useless and inconvenient member.

_Lateral versions of the phalangeal joints._—Lateral versions of the fingers are intimately associated with hammer finger in pathology, and the two distortions are sometimes combined. The lateral inclination, which seldom exceeds 25°, may affect either of the inter-phalangeal joints, but is more frequently in the distal phalanx. Like the “hammer” deformity, it is usually found in the little finger, and is symmetrical. The version is nearly always towards the radial side, and the movements of the joint are a little impaired. Amongst eight hundred children in the Hanwell School were found six cases, of which five were double and affected the little fingers, the sixth being in the fourth digit and unilateral; in two the version was associated with slight hammer flexion. It is occasionally seen in the index finger, and the version is then towards the ulnar side. The condition is rather unbecoming than inconvenient, and cases are seldom brought to the surgeon for relief. It is a result of irregularity of development, the condyle growing a little more rapidly on one side than on the other. The constancy of the radial direction of the version of the little finger is probably explained by the fact that any lateral pressure to which this digit is subjected is from the ulnar side, while in the index finger the pressure is more often from the radial side, and hence an ulnar distortion is here the more usual. The deflected joint may be straightened by the use for a few weeks of a narrow metallic side splint, jointed opposite the articulations. No operation is required.

Exaggerated forms of distortion of the fingers may occur in rheumatoid arthritis, gout, or chronic rheumatism, and in various nervous affections,[2] but these rarely call for surgical treatment.

CONTRACTIONS ARISING FROM INTERRUPTED EVOLUTION OF THE FLEXORS OF THE FINGERS, WITHOUT PARALYTIC OR SPASTIC COMPLICATIONS.

This condition necessarily belongs to the pre-adult stage of development. It is characterised by persistent flexion of one or more digits, without any articular abnormality, and unassociated with spasm or paralysis, but the contraction is of a different kind from that found in hammer finger and hammer toe. The degree of flexion varies with the position of the hand, and when the wrist is strongly bent forwards the fingers may be extended, perhaps completely, but extension of the wrist is accompanied by a return of the contraction, the degree of which increases progressively as the wrist extension is carried nearer to its limit. The power of grasp is little impaired. Any attempt to overcome the flexion by violence is met by powerful resistance, and great pain is induced. If the patient be anæsthetised, the contraction remains unaltered, but the resistance is felt to be of a peculiar elastic character, and yields to a slight extent during the application of passive force. The defect leads to great interference with the functions of the hand. The pain caused by anything that tends to stretch the shortened muscles induces a voluntary exaggeration of the flexion, and after a time the control over the extensors is apt to become impaired. The causes are often obscure, but some examples have been traced to traumatic injuries of the flexor side of the forearm in infancy or childhood. In any case the essential factor appears to be a trophic lesion of local or central origin, which retards or arrests the due growth of a muscle or a portion of a muscle without causing its atrophy or paralysis. The following cases will serve to illustrate the phenomena so far as they have come under my own observation:

CASE 1.—M. O., a domestic servant aged seventeen, was
admitted into St. Thomas’s Hospital in September 1889. On
examination the third, fourth, and fifth fingers of the right
hand were found to be flexed at the metacarpo-phalangeal and
inter-phalangeal joints—the two latter strongly, the former
slightly. When the wrist was fully extended the contraction
became more marked, and the distal phalanges of the ring
and little fingers touched the palm, but when the wrist was
fully flexed the fingers could be voluntarily brought into
a state of complete extension. The power of grasp was good,
although somewhat less than in the left arm; the bones were
normal in form and size; and the joints were quite free in
their movements when the flexors were relaxed by position. The
forearm muscles appeared to be of normal size. A small scar
was seen about two inches below the elbow, over the inner side
of the front of the arm, the result of a fall thirteen years
before. The patient was strong and healthy in appearance, and
showed no sign of neurotic disorder. She had never suffered
from rheumatism or any other severe illness, and the family
history appeared to be good. She stated that the contraction
began to appear in childhood, shortly after the injury to the
arm, but that it had been making more rapid progress in the
past eighteen months, during which she had been growing very
quickly. After a fruitless attempt to improve the condition
by passive motion and splint extension, neither of which was
well borne, it was determined to lengthen the tendons by
operation. On October 18, 1889, the patient was chloroformed,
and it was observed that the deepest anæsthesia caused no
relaxation of the contraction. A semicircular incision was made
over the inner side of the front of the forearm just above
the wrist, the convexity overlapping the tendon of the flexor
carpi ulnaris, the horns reaching to a line midway between the
radial and ulnar borders of the limb. The flap of integument
and fascia was reflected towards the radial side, exposing
the inner portion of the flexor sublimis. The tendon of this
muscle going to the ring finger was then isolated, transfixed
by a fine tenotomy knife, and split longitudinally for a
distance of two inches. At each end of the fissure so made
the tendon was divided in such a manner as to leave one-half
of the split portion attached to the proximal, the other to
the distal, end of the tendon. (Fig. 8.) The tendon, a very
slender one, to the little finger was similarly treated. The
effect of this measure upon the contraction was very slight.
The portion of the flexor profundus common to the middle,
ring, and little fingers was then drawn out and divided after
the same method, and the section was followed by immediate
and complete extension of the digits. When the fingers were
fully straightened, the ends of the divided tendons still
overlapped each other to the extent of about a third of an
inch, and these portions, in each tendon, were then carefully
sewn together by catgut sutures. The wound was then closed and
dressed antiseptically (without drainage), and the hand was
placed upon a plaster-of-Paris splint; the wrist and fingers
being moderately flexed, in order that no undue tension should
be thrown upon the united tendons. Healing took place by first
intention. At the end of a week the fingers were partially
extended, and four days later the extension was made complete,
the alteration of position on each occasion being effected
without difficulty, and at the expense of little pain. In the
middle of the fourth week after the operation a feeble power of
flexion had appeared. The patient was discharged on November
13, twenty-six days after the operation. Two months later
the condition had much improved, and the voluntary flexion,
although still weak, was almost complete as to range. All
the tendons had evidently united firmly. She was directed to
wear an extension splint at night, and to practise active
and passive movement at intervals in the day-time. At the
end of a further three months the patient, who lived in the
country, came again to London. She had been growing taller in
the interval, and said that the contraction had been gradually
reappearing. On inquiry it was found that she had neglected her
instructions as to extension and motion. Some slight return
of the flexion had appeared in the ring and little fingers,
and has since been steadily increasing, till it is now almost
as great as when she first attended. She has made no adequate
effort to oppose the retrogression, but has almost entirely
discontinued to use the affected hand. She is still, however,
able to move the fingers freely at all the joints. She desires
to undergo another operation; but has been advised to obey the
directions given to her after the first, and to wait until
her growth is quite complete before any more active surgical
treatment is undertaken.

DIAGRAMS SHOWING METHOD OF TENDON LENGTHENING.

A. Tendon split longitudinally; B. Section completed by incisions at extremities of fissure; C. Divided tendon elongated and sutured.]

The pathology of this case is very obscure. The contraction evidently depended upon a trophic lesion, perhaps due to the injury in childhood, involving the ulnar portion of the flexor profundus, impeding the growth of the muscle, and so preventing it from keeping pace with the normal growth of the bone, but not causing paralysis. The contraction of the flexor sublimis was evidently secondary. The recurrence of the deformity may be explained by the progressively increasing length of the bones of the forearm, the muscle remaining stationary; in other words, the original cause of the condition—the incapacity of the profundus for development—persisted, and led to a return of the effect. Under these circumstances it would obviously be advisable to delay a second operation until the osseous system had reached its permanent proportions. The operation I believe to be original; and so far as the restoration of continuity of tendon is concerned, the result proved a complete success. It might possibly be applied with advantage in various conditions as a substitute for tenotomy.

The operation was performed independently by Professor Keen,[3] about a twelvemonth after this case, and has since been adapted to lengthening and shortening of tendons by Drs. H. A. Wilson,[4] Colgan,[5] and Ochsner, in America.

CASE 2.—H. L., a youth aged seventeen, was admitted as an
out-patient at St. Thomas’s Hospital, in November 1890. He
complained of a contraction of the thumb and fingers of the
right hand of three years’ duration. The condition began
without apparent cause, and has increased progressively. He was
fairly well grown, but of somewhat delicate aspect. He had an
attack of rheumatic fever at the age of six, but had since been
in good health. The contraction was of the same nature as that
in Case 1, but less in degree, and involved all the digits. The
hand was well formed, and all the bones, joints, and muscles
were normal. The power of finger extension was complete during
flexion of the wrist. The forearm flexors are rather small,
but there is no distinct atrophy; the movements at the wrist,
elbow, and shoulder are perfect. He said that the defect
crippled him greatly for work, and that forcible extension
caused pain in the forearm. He was instructed to carry out a
system of massage, with active and passive movements of the
fingers and wrist.

CONTRACTIONS DUE TO UNBALANCED ACTION OF THE FLEXOR MUSCLES AFTER RUPTURE, DIVISION, OR DESTRUCTION OF THE EXTENSOR TENDON.

These accidents are not uncommon in ordinary hospital experience. The effect of such a solution of continuity over the back of the hand is to leave the first phalanx in a state of flexion, while the second and third phalanges may be voluntarily straightened without difficulty, especially if the metacarpo-phalangeal joint be passively fixed in the position of extension. The reason for this of course is that the common extensor, by virtue of its ligamenta dorsalia and its connection with the aponeurotic fibres derived from the interossei, acts with peculiar advantage upon the metacarpal phalanx, although it has no direct attachment to it, while its nominal “insertion” into the middle and ungual phalanges is subservient to the interossei and lumbricales, which are the true extensors of these bones. On the other hand, if the lesion fall just on the proximal side of the first inter-phalangeal joint, the first phalanx may be susceptible of almost complete voluntary extension; but the second and third phalanges are bent by the unopposed action of the superficial and deep flexors, because the influence of the true extensors, the lumbricales and interossei, has been cut off. In like manner, a division of the tendon over the middle phalanx leaves the terminal phalanx in the position of flexion; and a similar result follows the accident first described by Segond, in which the extensor tendon is torn away with a portion of the bone during forcible flexion of the ungual phalanx.

_Treatment._—If the injury be seen in the early stage and there is no loss of substance at the point of lesion, it may be treated satisfactorily by fixing the finger, hand, and wrist in full extension, to allow the passive approximation of the divided extremities of the tendon; but should the case not come under notice until a later period it will be necessary to cut down and suture the tendon. If there is loss of substance and the two ends of the tendon cannot be brought together, the treatment must vary with the position of the injury. In some cases, where the metacarpal portion of the tendon is involved, a good result may be obtained by joining the distal end to the adjacent tendon so as to bring it again within the control of the muscle, but if the digital portion be the seat of the lesion this is impracticable, and a remedy may be found by lengthening the tendon, either by splitting one or both ends and suturing the extremities of the portions detached, or by transplanting a portion of a tendon from a dog into the gap. As a last resource the traction of the flexors may be balanced by an elastic extension band replacing the destroyed tendon, and attached by one end to a little cap drawn over the finger, by the other to the dorsal aspect of a wrist gauntlet.

CONTRACTIONS ARISING FROM NUTRITIVE CHANGES IN THE MOTOR APPARATUS.

There are at least three well-known forms of pathological change in the motor apparatus of the forearm (independent of the ordinary paralytic or spastic conditions due to nerve lesions) that may give rise to contractions of the fingers. These are—the ischæmic paralysis of Volckmann, inflammatory processes in the muscular sheaths, and gummatous formations, or more rarely other tumour growths in the muscles.

(_a_) The affection described by Volckmann as muscular paralysis of ischæmic origin is now seldom met with. It is a result of prolonged immobilisation of forearm fractures by any form of apparatus that intercepts the free circulation of blood through the muscles and nerves of the part. When the splint is removed the hand is found painful, dusky, and swollen, and the fingers are bent like claws, any attempt to extend them causing great pain. Volckmann believed that the nerves in these cases have preserved their power of conduction, but that the muscular fibres are structurally injured and have lost their excitability. The lesion, however, is seldom of a permanent character, and the function may generally be restored by systematic active and passive movements, with massage, and if necessary the use of a galvanic current. Its existence is a reproach to surgery, since a careful observation of the hand and fingers during the use of splints will always give due warning of the danger.

(_b_) Diffuse inflammation of the inter-muscular planes and perimysial connective tissue may occur as a result of poisoned wounds, and other injuries, and may lead to a like deformity in the fingers. In a case under my own charge it was caused by a sting in the forearm by an adder. The injury was followed by the usual pain and swelling, accompanied by a painful contraction of the fingers, which lasted for nearly three months, but was ultimately relieved by the measures recommended for the ischæmic paralysis. Wounds implicating the flexors may occasionally lead to permanent contraction—either as a result of actual loss of substance, or in young subjects from interference with the development of the muscle (as in the case already mentioned). Under these circumstances the operation of tendon lengthening may be required if the endeavours to secure gradual extension are unsuccessful. König describes a case of flexion of the hand and fingers in a newly-born child, caused by a tearing of the flexors at the moment of disengagement of the arm in the course of delivery.

(_c_) Gummatous formations in the forearm flexors, causing painful contraction of the finger, are comparatively rare. A very interesting case of the kind is reported by Dr. A. G. Barrs in the _Medical Chronicle_ for May 1891. The muscle affected was evidently the flexor profundus in its ulnar portion; and the finger contraction which bore a superficial resemblance to Dupuytren’s disease, was complicated by other symptoms indicating a concomitant affection of a portion of the cord.

CONTRACTION OF THE FINGERS DEPENDENT UPON A TENDO-VAGINITIS OF THE BURSAL SHEATH OF THE FLEXOR TENDONS.

The following notes of an example of this somewhat rare condition under my observation may be of interest:

The patient, a girl, aged twenty, attended St. Thomas’s
Hospital for a swelling of the front of the right wrist, with
contraction of the fingers and complete loss of use of the
hand. She stated that the contraction appeared six days before
without apparent cause. On examination a large swelling was
found, extending upwards for about an inch and a half above
the anterior annular ligament, and distally along the ulnar
side of the palm as far as the root of the little finger. The
phalangeal joints of all the fingers were flexed, and any
attempt to straighten them caused considerable pain, while the
movements of the little finger were accompanied by a peculiar
coarse grating, that could be felt along the whole length of
the theca and in the palm, ceasing, however, at the level
of the carpus. The thumb was flexed and adducted, and the
movements of flexion and extension were painful, apparently
because they led to disturbance of the enlarged bursal
sheath of the finger flexors. The affection was evidently a
tendo-vaginitis involving the carpal bursal sheath of the
finger flexors and the palmar extension which brings this into
communication with the digital bursal sheath of the little
finger. The crepitation indicated that the intra-vaginal
portion of the tendon was roughened by inflammatory deposits,
and it is possible that these irregularities may lay the
foundation for a subsequent trigger finger. The case was
successfully treated by immobilisation of all the joints of the
wrists and fingers in plaster of Paris, followed by passive
movement as soon as the acute stage was passed.

A tendo-vaginitis of the extensors over the back of the hand may induce considerable functional impairment of the fingers, with more or less contraction at the metacarpo-phalangeal joints. Such a condition has been described by Vogt as an occasional result of gonorrhœa, and Verneuil has met it as a manifestation of syphilis. The majority of examples, however, occur without any ascertainable constitutional cause.

CONTRACTIONS DEPENDENT UPON INFLAMMATORY AND DEGENERATIVE CHANGES IN THE ARTICULAR STRUCTURES.

The deformities induced by gout, rheumatism, and rheumatoid arthritis fall more directly within the domain of the physician, while those due to tuberculous or traumatic lesions are of more immediate concern to the surgeon, but the characters which distinguish the various conditions from each other are of interest for every practitioner. The chief points bearing upon diagnosis are as follows: In the _gouty form_ the personal and family history of the patient, the acute and painful nature of the local inflammatory attacks, the presence of urate of soda deposits in the part, and the evidence of similar disease in other portions of the body. In _chronic rheumatism_, which is more often present in women and in the poorer classes, the moderately painful attacks of synovitis with crepitation, and evidence of wearing away of cartilage. In _chronic rheumatoid arthritis_ the presence of bony outgrowths around the margin of the articulation is the main element of distinction from the latter condition. In _tuberculous disease_ the personal and family history, the soft fusiform swelling, the tendency to breaking down of the morbid tissue, and the more or less complete destruction of the articular capsule in the later stages. Contractions with ankylosis may also occur in acute rheumatism and acute rheumatoid arthritis, and in a peculiar neuropathic condition simulating the latter. These will be referred to in connection with the contractions of the toes. In the traumatic forms the history and marks of injury will usually be sufficient for diagnosis; but it must, of course, be understood that common injuries, by weakening the resistance of the part, may localise the attack of a specific disease, such as tuberculosis or gout, and hence the onset of tubercular or gouty arthritis may coincide with an ordinary traumatism. It is, as a rule, only in the tuberculous and traumatic forms that the surgeon is consulted. The treatment must, of course, be based on general principles; but it is necessary to recollect that an ankylosed finger-joint nearly always renders the digit worse than useless, especially if the articulation be fixed in the position of extension.

It is only necessary to mention that contractions without joint lesion may occur in the fingers as a result of disease or injury of the bone. Simple fracture in the neighbourhood of an articulation may produce a deformity closely resembling that of dislocation. Caries or necrosis may also lead to a breach of continuity in the shaft of a bone, and various distortions may follow the cure of the disease.

CONTRACTIONS OF PARALYTIC AND SPASTIC ORIGIN FOLLOWING LOCAL INJURY.

A complete account of the various conditions falling under this denomination would require an entire course of lectures, and it is hence necessary to confine our attention to those forms which belong to the surgeon rather than to the physician.

Spastic conditions following local injury are very rare. An example was brought before the Medical Society by Dr. Beevor[6] in April 1888, in which a contusion of the right hand in a boy of fifteen was followed five days later by permanent contraction of the hand with total anæsthesia as far as the shoulder and loss of the muscular sense, the movements of the arm and forearm remaining unimpaired. In the discussion a similar case was referred to by Dr. Hadden.

All the nerves which govern the muscles acting upon the fingers are liable to injury—the median and ulnar more particularly by wounds, usually in the wrist, and the musculo-spiral by pressure of a crutch.

An injury involving solution of continuity of the _Ulnar nerve_ is a very grave accident, unless it can be treated surgically without any long delay. The symptoms are such as might be inferred from a knowledge of the distribution of the branches. It will be remembered that the nerve supplies the flexor carpi ulnaris and ulnar half of the flexor profundus digitorum in the forearm, the whole of the muscles of the hand, except the abductor, opponens, and outer head of the flexor brevis pollicis, and the two inner lumbricales, and it gives sensation to the skin over the inner side of the wrist and hand, to the palmar and dorsal surfaces of the little and ulnar half of the ring finger, and sometimes also to the radial half of the ring finger and ulnar half of the middle finger. The effects of the nerve lesion will, of course, vary with the position of the injury. If the trunk be divided just above the wrist, the branches to the two forearm muscles and the cutaneous branch to the back of the hand and fingers will be spared; but the palmar cutaneous filament will probably be implicated by the wound. The paralysis of the interossei produces an inability to flex the first phalanges and extend the second and third, while the unbalanced action of the extensor, and superficial and deep flexors, causes the position of super-extension of the metacarpo-phalangeal joint with flexion of the inter-phalangeal joints, which constitutes the _main en griffe_ of French pathologists (Fig. 9). The clawing is chiefly marked in the ring and little digits, especially the latter, but is lessened in the index and middle fingers by the continued integrity of the first and second lumbricales. There is, in addition, great loss of power in flexion and adduction of the thumb, and complete loss of sensation over the front and distal part of the back of the little finger and the corresponding portion of the ulnar side of the ring finger. At a later stage nutritive changes appear in the paralysed structures, and the deformity becomes complicated by the atrophy of the skin and subcutaneous fat, the hollowing of the interosseous spaces and the wasting of the thenar and hypothenar eminences. If the nerve be injured at the elbow, the paralysis of the two forearm muscles, and the loss of sensation over the ulnar side of the back of the hand would add to the symptoms, but would not sensibly affect the deformity.

Deformity in case of wound of ulnar nerve above wrist.]

The treatment is to seek for the divided ends of the nerve, and to unite them if possible. Should the interspace be too great to allow direct suture, an attempt might be made to restore continuity by cutting a long flap from the proximal extremity of the nerve and bringing it down to the distal end; or by the transplantation of a portion of nerve from an amputated limb, or from one of the lower animals. Where the wound lies immediately above the wrist, it is well to remember that the ulnar nerve and vessels are covered by a fibrous band, which passes from the radial side of the flexor carpi ulnaris tendon in this situation to blend with the anterior annular ligament. It should also be recollected that the deep branch of the nerve, which is occasionally implicated in penetrating wounds over the hypothenar eminence, runs around the ulnar side of the tip of the unciform process, and may there be exposed without much difficulty.[7] After operation the hand should be placed in a position of adduction and flexion, and the wound dressed antiseptically. Should this measure fail, the apparatus devised by Duchenne may be applied to replace the action of the paralysed muscles.

_Musculo-spiral paralysis_ may be induced by ordinary wounds or contusions, by fractures of the humerus, or by long-continued compression of the nerve against the bone, either by the handle of a crutch, or while the patient is sleeping with his head resting upon an arm which is supported by the back of a chair. The consequences are paralysis of the elbow extensors, the supinator longus, the supinator brevis, and the whole of the extensors of the wrist, thumb, and fingers; and loss of sensation over the cutaneous areas supplied by the nerve in the arm, forearm, and hand. For the patient the most striking symptoms are the flexion of the wrist and fingers, the loss of power to abduct the thumb, and especially the enfeeblement of grasp due to the inability to fix the wrist during the action of the finger flexors. If the wrist be held firmly by the other hand, or by another person, in the position of extension, the power of grip becomes restored. A similar condition is present in lead poisoning; but here the loss of power is confined to the extensor muscles, and the supinator longus remains unaffected. The possibility of a crutch paralysis should lead the surgeon to warn every patient who is compelled to use the implement, in order that the paralysis may be prevented, or, should it occur, that it may be perceived and arrested in its earliest stages. When the condition has become established, an attempt should be made to restore function by massage and electricity, and if these fail, the nerve should be exposed at the seat of injury, and its continuity restored by the excision of the atrophic portion and union of the two free extremities.

In paralysis of the _Median nerve_ by a wound above the wrist, the most distressing symptoms are referable to the trophic lesions in the integuments of the thumb, index, middle, and ring fingers (radial side) on their palmar surface and the distal half of their dorsal aspect. There is, in addition, a partial loss of power of flexion and abduction of the thumb, with wasting of the thenar eminence and some interference with the delicacy of the movements of the index and middle fingers, owing to the paralysis of the first and second lumbricales. If the nerve be divided above the elbow, the pronators and all the flexors of the wrist, thumb, and fingers, except those supplied by the ulnar nerve (flexor carpi ulnaris, and ulnar half of the flexor digitorum profundus), are paralysed, and consequently the hand is, for all practical purposes, quite useless. The rules for treatment are similar in principle to those laid down for injuries of the musculo-spiral and ulnar nerves.

_Spastic Paralyses_, in connection with central disease, need not be discussed; but the surgeon is sometimes consulted for conditions of persistent spasm which apparently depend upon excessive use of certain muscles. Erichsen refers to, and figures, a case of flexion with pronation attributed to cutting with heavy shears. He notes that when the wrist was extended the fingers became flexed, and when the wrist was extended the fingers became bent in. It is not stated whether the permanency of the contraction was tested by the use of an anæsthetic, but the patient, as well as another in whom the extensors were affected in like manner, became cured by means of friction and galvanism, with the use of a straight splint. A case of spastic contraction of the right little finger of thirty-five years’ duration was recently in the Mile End Infirmary. The flexion of the finger is associated with slight adduction of the hand, but the parts can be straightened completely by passive force. The condition is attributed to a wound near the elbow. There is no lesion of sensation.

The group of affections known as _Writer’s cramp_ usually fall within the province of the physician, and will only be briefly referred to. They are of uncertain pathology, vary considerably in their manifestations, and, although most common in persons much engaged in writing, are by no means confined to these. The symptoms may assume three different types—spastic, paralytic, and tremulous—affecting the muscles of the hands and forearm, and these may be combined in various ways. The prognosis is unfavourable; but the treatment found most hopeful is to relieve the affected muscles from the strain to which they have been accustomed, and strengthen them by massage and galvanism. Interference by surgical operation has been unsuccessful, except in one case, in which Stromeyer divided the flexor longus pollicis tendon.

CONGENITAL AND INFANTILE CONTRACTIONS.

These are usually of paralytic origin, but include a proportion of cases of true hammer finger. The common form is that already described by Mr. William Adams (Medical Society, December 1890), in which the inter-phalangeal joints of one or more fingers (most frequently the fifth) are flexed, and the integument on the palmar aspect forms a longitudinal fold, which becomes tense when an attempt is made to straighten the digit; the metacarpo-phalangeal joint is super-extended. At first the finger may be fully extended by passive force, but after a few years the position of flexion at the first inter-phalangeal joint is rendered permanent by imperfect development of the ligamentous fascial and even cutaneous structures in front of the articulation, while the terminal phalanx usually remains more or less helpless. The condition is probably dependent upon an infantile paralysis of the flexors of the affected digit. The use of friction, passive movement, and electricity, may be of value in the early stages.

TRIGGER FINGER.

The description of this curious affection has been left until the last because its true nature is still an unsolved problem, and it is hence difficult to place it in any of the groups already described. It is indeed rather a pathological curiosity than an important item in surgical disease, and many surgeons of long experience have never met with a single example. Of the mechanism of its causation we know almost nothing, of its ultimate tendencies we know little more, and its morbid anatomy is almost entirely speculative. Nevertheless, it has a literature extending over forty years, and comprising nearly a hundred separate contributions, the last of which, a model in its way, is a monograph of 250 closely printed large octavo pages, the work of Dr. Carlier.

Trigger finger, the _doigt à ressort_ of French authors, may be defined as a peculiar defect in the motions of the digit, consisting, first, of an impediment which obstructs the movement of flexion or of extension, or of both, followed, if the motive force be continued, by a sudden cessation of the resistance, and a brusque, spring-like action that often bears a remarkable resemblance to that which accompanies the opening and closure of the blade of a penknife. The first observation was that of Notta in 1850. A finger attacked by this affection generally lies when at rest in a position of flexion, and by a voluntary effort or by passive force may be straightened, with the peculiar result described in the definition, the resistance to extension suddenly yielding with a trigger- or spring-like action; and the same phenomenon is usually but not necessarily repeated when the digit is again bent. In exceptional cases a reverse condition obtains: the passive finger is kept in a state of extension, and it is during flexion that the trigger phenomenon is elicited. The movement may be merely inconvenient, or it may be more or less painful. The sign may be constant, accompanying every movement, or it may be intermittent, disappearing and recurring without any obvious reason. It is usually confined to a single finger, but it may be multiple. The digits most frequently involved are the middle finger, the ring finger, and the thumb, while the index and little fingers are relatively free, and the right side is more often affected than the left. It is rather more common in women than in men (in the proportion of three to two); and much more frequent in adults than in children, but may appear at all ages. The etiology is ill understood. In many cases an important influence, direct or remote, has been assigned to rheumatism; in others the condition has been attributed to injuries of various kinds; in others to occupations necessitating over-use of the digital articulations (as in sempstresses); but no cause has yet been recognised which can account for any large proportion of the examples.