General information
The Germanic tribes used to call the thumb “Dumo” or “Dume”, which was supposed to mean “the fat one” or “the strong one”. In the course of time, this term developed into the word “thumb” as we know it today. The thumb (Pollex) forms the first finger of a hand and can be opposed to the other four fingers.
Because of this anatomical peculiarity and the more extensive movement options it offers, the thumb is given a special role among the fingers. Each finger has three phalanxes. The thumb, however, is the exception and consists of only two phalanges.
A phalanx proximalis, which is closer to the trunk of the body, and a phalanx distalis, which is further away from the body. The question of why the thumb consists of only two phalanxes has occupied anatomists since the beginning of time and can still not be answered with certainty. The thumb saddle joint (Articulatio carpometacarpalis pollicis) gives the thumb its special character in relation to the other fingers and optimizes the grasping function of the hand enormously.
The thumb saddle joint is located between the large polygon bone (Os trapezium) and the first metacarpal bone. The joint surface of the bones here has both concave (inwardly inclined) and convex (outwardly inclined) areas. For this reason, the bones can be moved back and forth or from one side to the other.
Rotations, however, are only possible to a limited extent. Due to the fact that this joint can move in two axes, it is similar to a conventional ball joint. Numerous ligaments stabilize the saddle joint of the thumb, which is surrounded by sheaths of connective tissue, the tendon sheaths.
These protective sheaths prevent ligaments, nerves and surrounding vessels from being severely strained and possibly damaged during contraction of the muscles of the forearm. The long extensor tendon (flexor tendon) of the thumb even has its own tendon sheath. The extensor tendon of the thumb saddle joint includes the muscle extensor pollicis brevis, muscle pollicis longus and muscle abductor pollicis longus. Musculus flexor pollicis brevis, Musculus flexor pollicis longus, Musculus abductor pollicis brevis, Musculus opponens pollicis and Musculus adductor pollicis are primarily counted among the flexors of the thumb saddle joint.
Pain in the thumb
In the group of women over 50 years of age, one in two already complains of problems and pain in the thumb. For men, on the other hand, it is only one in ten. This can be explained by the hormonal influence that women are exposed to during their menopause – the reduced production of oestrogens (the female sex hormones) apparently makes the joints, nerves, ligaments and vision more sensitive and susceptible to disease.
The pain can present itself as pulling, drilling, shooting or stabbing, especially when moving in any direction. However, since the thumb is required for just about every movement, it hurts permanently and can lead to a severe restriction of movement. In extreme cases this can lead to occupational disability.
In the case of arthrosis of the thumb saddle joint, the pain results from wear and tear of the thumb. The lower part of the thumb, the thumb saddle joint (which is located very close to the wrist) is affected by wear and tear. In technical terminology, this disease is also called rhizarthrosis.
Wear and tear in rhizarthrosis is age-related, i.e. not caused by a genetic predisposition or any other initial disease. The pain that occurs is usually stabbing and pulling and only occurs at the beginning of rhizarthrosis when the joint is put under a lot of strain, for example when a soda bottle is opened. The cause of the pain is an inflammation, which is located between the bony components of the thumb saddle joint and which causes discomfort with every movement of the thumb and the associated rubbing of the bones against each other.
In the early stages of the disease, anti-inflammatory ointments and creams can still provide sufficient relief. If the wear and tear on the joint progresses and the pain becomes increasingly severe, the highly anti-inflammatory drug cortisone can be injected directly into the joint capsule to relieve the pain. Sometimes it is also advisable to apply a rigid splint and thus immobilize the hand for a while and not to put any more strain on the joint.
If all these measures do not provide sufficient relief and the pain becomes increasingly severe, a surgical procedure can be considered in which the arthritic, worn bone is removed and the joint is stabilised with ligaments instead. Since it is a relatively minor procedure thanks to the latest medical technology, patients are usually able to put weight on the thumb joint within a few weeks after the operation and its functionality is also almost as good and strong as with a natural joint. Another possibility would be the use of a thumb saddle joint prosthesis.
Another disease is the Heberden’s arthrosis, also known as Bouchard arthrosis. This disease, also mostly found in older women, often manifests itself with small nodules. These small nodules usually form at the end joints and middle joints of all fingers, and are therefore also at the thumb joint and around it.
They cause pain when the thumb is moved. They are also in the way and hinder the thumb in its movement, so that there can be restrictions and the thumb loses strength. Where exactly and why these small knots form is not yet fully understood.
There is, however, a connection with wear and tear under heavy and prolonged stress, inflammation and hormonal influences. Often, when a woman falls ill with Heberden arthrosis, the mother is also affected. Fortunately, however, the nodules fortunately no longer cause pain and will soon recede if they are treated with anti-inflammatory drugs, such as cortisone ointments or injections.
If all attempts at treatment with the usual medications fail, there is the possibility of a surgical intervention and surgically stiffening the joint with special screws or even replacing it with a prosthesis. If the pain in the thumb occurs mainly during stretching, it can be tendovaginitis de Quervain, commonly known as “housewife’s thumb”. This is a symptom of overstrain which also affects women over 50 years of age.
The constant overloading of the thumb and its tendon and ligament apparatus can lead to tendosynovitis, which causes pain whenever an attempt is made to stretch the thumb straight. It is not the tendon itself that is inflamed, but the actual protective sheath in which the tendon runs. If the thumb is permanently overstretched, however, the tendon moves incessantly in this tendon sheath, thus causing irritation and inflammation of the tissue.
Classical movements are, for example, housework, long hours working on the computer and typing on the smartphone. As a rule, anti-inflammatory cortisone-containing ointments and creams already help. In more severe cases, the joint can be immobilised with the help of a splint, giving the joint the time it needs to regenerate itself.
After the tendosynovitis has healed, it is advisable to undergo physiotherapy and learn about dangerous and harmful movement patterns in order to avoid them in the future and thus prevent a recurrence of the disease. Carpal tunnel syndrome is a disease that can occur after years of overstraining and overloading the wrist and especially the thumb. Here too, hormonal changes play an important role, so that once again women over 50 years of age make up the bulk of the patient population.
If someone has already suffered from tendosynovitis of the hand, the risk of developing carpal tunnel syndrome increases for him/her even more. In carpal tunnel syndrome, the connective tissue in the wrist, which is constantly overloaded and thus becomes inflammatory and degenerative over time, presses on the median nerve, a nerve that runs right through the middle of the wrist, on the inside of the forearm, and is responsible for the supply of the hand. Thus, the nerve permanently has the feeling of being exposed to a stimulus and transmits this information to the brain, which in turn processes the incoming stimulus as usual and judges it as an unpleasant tingling sensation, a numbness in the hand or simply as pain.
Most often the complaints occur during certain movements of the hand, in which the nerve is additionally constricted and irritated, or at night, when the hand is perhaps in an unfavourable position. The only definitive treatment option for carpal tunnel syndrome is surgery, in which the joint capsule of the wrist is opened and dilated, giving the nerve more space again and eliminating the irritating permanent irritation by the connective tissue. The procedure is part of the medical routine and is usually relatively uncomplicated, but it must be remembered that the hand must be immobilised for a while after the procedure and, of course, no promise of complete recovery can be given.
A further, widespread disease of the thumb is the disease called “fast thumb” or also “snap thumb”, Tendovaginosis stenosans. Here, too, permanent overstrain coupled with the hormonal changes of the menopause mean that it is primarily women over 50 who are affected. A certain genetic predisposition to “snap finger” is also being discussed.
Due to changing processes in the tissue, the flexor tendon of the thumb swells over the years and small nodules form on the flexor tendon. These small nodules are not problematic in and of themselves, but become so when they are located in an unfavourable place, namely near the so-called ring ligament of the thumb. The flexor tendon runs through this.
However, if these small nodules are located there, they get caught on the ring band and the thumb jerks back when they have pressed through the ring band and come loose again. Tendovaginosis stenosans can in principle affect all fingers, but since we humans use the thumb most frequently and intensively, it mostly occurs here. A small surgical intervention can quickly remedy this situation.
The ring ligament of the thumb is severed and the nodules can no longer restrict the flexor tendon of the thumb in its movement. Another disease which this time can affect not only older women but also young girls is the ganglion. Theoretically, the ganglion can also occur on all fingers, but usually the two thumb joints are affected.
In simple terms, a ganglion is a hard capsule filled with fluid that presses on the joint capsule with its coarse structures and thus causes pain. These ganglions are often caused by a weakness of the connective tissue. Here too, the therapy consists of surgical removal of the liquid-filled balloon.
Behind a painful thumb or thumb joint and small nodules in and on the joints, tendons and ligaments, rheumatic disease or gout can of course also be hidden. A doctor can diagnose this by thoroughly examining the affected area, palpating it, using ultrasound and having the blood tested for special components that are characteristic of a disease of this type. The therapy is then of course completely different from the problems described above.
