US 2388330 A
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Nov. 6,1945. M. JUNGMANN WRIST PROTECTOR Filed Aug. 5,1943
2 Sheets-Sheet 1- INVENTOR.
'Marfih Dogma/m v M, ATTORNEY Nov. 6, 1945. M. JUNGMANN WRIST PROTECTOR Filed Aug. 5 194:5 I 2 Sheets-Sheet 2' IN BVTOR. Mqrf/n Jim ATTORNEY Patented Nov. 6, 1945 UNITED STATES PATENT OFFICE V 2,388,330 s I WRIST PROTECTOR Martin Junginann, New York, N. Y. Application August 5, 1943, Serial N... 497,478
This invention relates to a device for protecting and/ or supporting the wrist and hand and/ or elements thereof.
The construction of the human hand enables the individual to perform a multitude of manipulations in a great variety. This is made possible by the enormous number of combinations in which the elements forming the hand e. g. bones, ligaments, capsules, and muscles, may be brought into action for each single task. The efficient action of the hand dependsupon the correctly balanced interplay of these elements, which exert adequate strength from within, or counterbalance and withstand forces acting upon the hand from without. As long as the forces acting within the hand and those acting from without are balanced within the limits determined by physiological limitations of the muscles and by the structural resistance of the levers and their junctions, the conditions will be normal and will not cause harm or damage to the organ. It is only when said limits are exceeded as a consequence of undue strain, that the symptoms" of overstrain and fatigue occur.
As muscles and nerves have only a limited working capacity and are subject tofatigue, the
equilibrium in the interplay of muscles, and the condition of their tone is easily disturbed. This is often the case, as many of the tasks for which.
the hand is used, are to be performed over a relatively long period of time, and, therefore tiring. Furthermore, there are many manipulations, in which one single muscle-group is unduly strained unilaterally. As a consequence, the correct. leverage may be lost, and the working conditions for all groups of muscles may be changed unfavorably. In such cases, one muscle-group will develop more traction than its counterpart, and cause deviation of the lever more and more toward one side. In the course of progressive fatigue, the tone of the muscle will increase, and thereby the muscle become shorter than it was or normally should be. Hand in hand with this one-sided active contraction, goes a passive overstretching and overextension of the muscles on the opposite side of the lever, accompanied by an increase in their length.
In addition to this kind of pathogemc phenomena, there are other causes resulting in. disturbances and damages of the hand,
Primarily the human hand is built for use in traction whereby pull is exerted in the direction from the elbow toward the fingers or in the opposite direction. This means that the main forces act along the longitudinal axis of theforearm and the hand, with no or little rotary or torsional moments brought into action. However, in many cases hands are used in such a mannerthat rotary moments and torsions have to be produced or counteracted. This kind of action is particularly tiring for the muscles which give in, and cannot stop the spraining of the joints withinthe wrist.
Another kind of damage may be caused by the necessity of using the hand for supporting weights or for pushing heavy loadsor for absorbing shocks. In these cases, the forces acting along the longitudinal axis of the forearm, have a compressing and jamming effect upon the wrist parts which are squeezed in, compressed and often displaced out of the proper alignment.
One of the efiects of overfatigue of the muscle is the loss of the relaxing ability, and, therefore, lack of rest and recovery when not in use. An overtired and overexcited muscle remains in hypertonic, cramped, spastic condition, and develops tensions, which usually last for a long time, and hold the tissues of the joints under abnormal, harmful pressure. This state of reflex-hypertonus is an intermediary stage which occurs before an actual deviation of the joint from its middle position takes place. Such shifting of the joint out of its balance occurs when the protectingmechanism against, overstretching of the muscles breaks down, as a consequence of continued abuse of the hand in spite of symptoms of overfatigue. The symptoms in this phase may be p v ness, weakness, clumsiness, unreliability, and, at times, even the sense of paralysis. These symptoms are accompanied by objective signs, such as congestion, swellings, exudation, inflammatory reactions, tenderness on touching, rigidity, etc. In a later phase of this condition, changes in the range of excursions in the joint, and deviations from the normal position are found, accompanied by changes in the shape of the hand and in the consistency of the tissues. In the course of such development, the unbalanced hand may be affected in various ways on ligaments and cartilage.
such as sprains, strains, lesions of ligaments and joints, which often may result inso-called arthritic or -arthrotic conditions. Under these conditions, undue pull, and transmitted jogs and jolts, affect the insertions of the muscles on the arm to the hand and fingers.
bones. The periosteal tissues then often become irritated and inflamed and produce periosteal reactions, such as pain, swelling, inhibition of motion, etc.
Owing to the fact that the muscles of the hand proper overlap not only the wrist-joints but also the elbow joints and insert partly even on the humerus (upper arm bone), primary disturbances of the wrist may manifest themselves in the elbow region. Upon progressive fatigue and forced continued use of the hand, the organism tries to compensate for the insufficiency of primary muscles, by bringing into play a suitable group of muscles in the adjoining region, i. e. the elbow and upper-arm. Thus, as a consequence of pathological fatigue and unbalance originally present within the wrist, pathological effects may manifest themselves in the elbow-, shoulder-, and even neck-region.
The above described pathology requires the provision of proper care. In many cases, however, circumstances do not allow proper care and sufiicient rest for the recovery of the affected organ. As a rule, workers cannot afford to stop their work for a, longer period of time, and they cannot work with their hand in protective casts or splints.
For this reason, various attempts have been made to protect the wrist by means of straps or cufis which. are adapted to tighten the wrist firmly and fix the joint by constriction. The known devices of this type may be of use under special circumstances, 1. e. during heavy work, in spite of the fact that they cause considerable tightening of the tendon sheets running from the fore- This interferes, of course, with the finer action of the muscles and the blood circulation, as it necessarily ties up the free flow of blood, at least in the venous part. Such effects make the use of the usual wristcuifs inconvenient and harmful.
The main object of the present invention is to provide a device adapted to protect the hand fromundue strain without interfering with the natural functions of the elements included in or forming the hand.
Another object ofthis invention is to provide a device adapted to limit the excursion of the wrist-joints to a sufficient extent for protection.
It is also an object of this invention to provide a device which is adapted to guide the movements of the hand within a reduced range by tracks of adequate design and dimensions in order to enable the hand to move without marked interference of action and without constriction.
A further object of my invention consists in providing a device which is adapted to serve as a support for the hand while not in use, so as to induce the hand to relax by allowing the hand to lean against a firm supporting element. Other objects and the advantages of the invention will appear from the following specification and claims, and the appended drawings.
The wrist-protecting device according to my present invention consists of a cuff-like body consisting of a suitable unextensible material, for example leather, plastics, fibrous materials and fibrous compositions, said body being formed or molded in such a manner and dimensions as to accommodate the wrist. It is adapted to cover the back of the hand up to some distance, preferably A1"- from the distal knuckles of the metacarpals, and bends and turns around the metacarpal bones of the thumb and the fifth finger, respectively. On the palm of the hand it must accommodate and fit the ball of the thumb, and the ball of the fifth finger. The material forming the device is relatively rigid and unyielding in the direction of the longitudinal axis of the device, but sufiiciently flexible around said axis in directions transversely thereto.
A preferred embodiment of the invention is shown by way of example in the appended drawings which form a part of this specification, and in which Fig. 1 is a plan view of the palm of a left hand provided with a protecting device according to my present invention;
Fig. 2 is a back view of the hand and the device shown in Fig. 1;
Fig. 3 is a diagrammatic dorsal view of a left hand indicating the bone system of the hand, and the wrist-protector applied thereto, while Fig. 4 is a diagrammatical, planar view of a left hand;
Fig. 5 shows a diagrammatical cross-sectional view of a hand and the protector applied thereto.
Referring now to the drawings, 1 is the protecting device covering the back of the hand up -to some distance from the distal knuckles 2 of the metacarpals, as best shown in Fig. 3. As best shown in Fig. 5, the device bends and turns around the metacarpal bones, 3, 3' of the thumb, and the fifth finger, respectively. On the palm of the hand it accommodates and fits the ball 4 of the thumb and the ball 5 of the fifth finger.
The device is closed on the dorsal plane of the hand, as shown in Fig. 2, but is open on the volar side, as shown in Fig. 1. The edges 6, 6 run approximately paralle1 to each other along the wrist and the forearm, and then turn in a smooth curve I, l to the back of the forearm.
The wrist protector covers the forearm up to about one inch above the knuckle 8 of the ulna,
and the dorsal plane 9 of the device is so molded that it can accommodate said knuckle of the ulna in an adequate cavity.
The profiles of my wrist-protector are so shaped that they are adapted to give freedom of action to the wrist as the pivot in all directions to about of the physiological range of excursion. An elastic strap I0 is provided on the volar side of the wrist in the height of the knuckle of the ulna. This elastic strap, which can be tightened or loosened, f. e. by means of a buckle l l, and fastened by means of clasp l2 and button I 3, serves for joining together the end portions l and l" of the device, and. for putting on and removing the device. The device is held in its proper place by means of an unelastic oblique strap l4, running from the dorsal side of the space between the thumb and index finger to the ball of the fifth finger on the palmar side. Strap l4 may be made adjustable in length. I prefer to make this strap or lace rather narrow and of a soft and pliable material so that it does not disturb the use of the hand.
If desired, elastic steelsprings H can be fixed and pivoted to the lower edge I5 of the device, and fastened to the finger by means of loop it of leather or another material. This additional element, which serves for the particular guidance of a single finger or several fingers, may be of special use for the thumb, the basal joints of which are particularly unstable. Owing to its very frequent exposure to extraordinar strain and unfavorable mechanical exertion, the thumb is affected most frequently, and, therefore, needs increased protection.
The wristprotector according to my present invention does not constrict or tighten th wrist, but
gives freedom of action and movement within 90 of the physiological excursion. The excursions of the hand are checked in the following manner:
Due to the shape and the material of the device which yields to fiexion around the longitudinal axis, it is sufficiently rigid and unyielding in any other direction. In dorsal flexion of the wrist it takes up the pressure of the flexed metacarpal bones, and transmits it to the bones of the forearm whereby the movement of the hand is stopped by the firm resistance of said bones on both ends of the device, and the device itself. A similar procedure takes place in the lateral defiexions of the hand, i. e. the radial or ulnar abduction, respectively, where the metacarpal bone of the thumb is checked by the radius due to the resistance of the device, whereas in the ulnar deviation the pressure of the fifth metacarpal bone is taken up by the ulna. The defiexion toward the palmar plane is stopped on the fifth metacarpal bone in a similar manner, and transmitted to the ulna. In addition to this, the increased tension of the elastic strap on the palmar side of the wrist, prevents opening of the device and hampers further fiexion on the radial side which is combined with ulnar abduction. The torsion around the longitudinal axis is arrested partly by adhesion and friction of the well fitting walls of the device and the hand, and also by fixation by strap [4.
The firmness in various directions of my wristprotector can be increased, if desired, by the incorporation of tempered and adequately shaped steel bands or equivalent means.
My wrist-protector may be used in different ways, depending upon the particular need of the individual. It may be worn during strenuous work as a protection against undue stress, or as a resting bed worn for hours or continuously, for conditioning and facilitating relaxation of the muscles before or after work. Furthermore, the
device may be worn in order to guard a weak and unbalanced wrist after injury, assisting the medical after-care when casts or splinting are not necessary. As a means of prevention, the device may be employed to avoid overstrain of the hand by certain types of work, such as typing, work with riveting tools or machines, etc.
Experience has shown that in proper use of the device a damaging effect never occurs. As the effects of a primary disturbance in the region of the wrist may spread and affect the whole functional unit of the upper extremity, the use of my wrist-protector is also useful in cases where elbow, shoulder or neck-region are afiected secondarily.
It is to be understood that my invention is not limited to the specific embodiments presented herein for illustration, and is susceptible of various modifications within the scope and spirit of the invention as defined in th appended claims.
1. A wrist-protector consisting of a cuff-like body of an unextensible material yielding to flexion around its longitudinal axis but only slightly yielding in other directions, said body being adapted to accommodate the wrist, and
form a continuous cover on the back of the hand,
said cover slightly extending beyond the knuckle of the ulna, while its lower edge is spaced AW-V from the distal knuckles of th metacarpals, said body bending and turning around the metacarpal bones of the thumb, and the fifth finger, respectively, and accommodating the ball of the thumb and the ball of the fifth finger on the palm of the hand, being open on the volar side of the hand, said body being provided with an unelastic holding strapprovided in the space between the thumb and index finger, and with an elastic strap for joining together spaced end portions of the wrist-protector on the volar side of the hand.
2. A wrist-protector consisting of a cuff-like body of an unextensible material yielding to fiexion around its longitudinal axis, but onlyslightly yielding in other directions, said body being adapted to accommodate the wrist, and form a continuous cover on the back of the hand, said cover slightly extending beyond the knuckle of the ulna, while its lower edge is spaced from the distal knuckles of the metacarpals, opposite end portions of the body being spaced and adapted to be joined on the volar side of the hand, the wrist-protector being provided with at least one steel spring fastened and pivoted on its lower dorsal edge, said steel spring being adapted to accommodate and protect a finger.
3. A wrist-protector consisting of a cuff-like body of an unextensible material yielding to fiexion around its longitudinal axis, but only slightly yielding in any other direction, said body being adapted to accommodate the wrist, and
- form a continuous cover on the back of the hand,
said cover slightly extending beyond the knuckle of the ulna, while its lower edge leaves free the distal knuckles of the "metacarpals, opposite end portions of the body being spaced and adapted to be joined on the volar side of the hand, said body being provided with means for holding it in place, said means running from the dorsal side of the space between the thumb and index finger to the ball of the fifth finger on the palmar side, and with means for connecting spaced end portions of the body on the volar side of the hand, said wrist-protector being adapted to guide and protect the elements of the hand without interfering with the natural functions of said elementls.
MARTIN J UNGMANN.