Introduction
The tabatière, also known as foveola radialis, is a small, elongated triangular depression on the thumb side (radial side) of the carpal. It is particularly prominent when all fingers are held extended and the thumb is spread apart. Since snuffers used to put their snuff in portions into the depression and inhale from it, it is also called “Tabatière” (French for snuff box). It contains important conducting pathways, such as the radial artery and a branch of the radial nerve, which sensitively innervates the skin of the thumb on the back of the hand.
Anatomy
On its long sides, the tabatière is bounded by the tendons of the thumb muscles – the Musculus abductor pollicis longus (long thumb spreader), the Musculus extensor pollicis brevis (short thumb extensor) and the Musculus extensor pollicis longus (long thumb extensor). The bottom of the tabatière is formed by the lateral part of the radius and a carpal bone – the scaphoid bone, also known as os scaphoideum. The roof of the tabatière is formed by the retinaculum extensorum – a firm, connective tissue band under which the tendons of the finger extensors run.
The Retinaculum extensorum ensures that the tendons of the extensors remain firmly attached to the bone during hand movements and do not lift off. The Tabatiere contains the radial artery, the radial artery with spokes, as important structures, as well as a branch of the radial nerve, which sensitively innervates the skin on the thumb side of the back of the hand. The pulse of the radial artery can also be easily felt in the Tabatiere.
Thumb saddle joint arthrosis
The thumb saddle joint is formed by a carpal bone (Os trapezium) and by the base of the first metacarpal bone (Os metacarpale I). The thumb saddle joint lies directly under the tabatière. The function of the thumb saddle joint is to allow the thumb to move freely, allowing precise movements, such as the pointed grip to the fingers or the key grip.
Thumb saddle joint arthrosis is the wear and tear of the cartilage in the thumb saddle joint. This leads to a painful restriction of movement and a reduction in the strength of the thumb. In addition, there is often a swelling or even a deformation of the joint visible from the outside.
The X-ray image shows a narrowed joint space and bone spicules, which are typical signs of joint wear. Sometimes, free joint bodies can also form in the gap, which further intensifies the pain of movement. Common causes of thumb saddle joint arthrosis are earlier fractures of the metacarpals or carpal bones, as well as rheumatic joint diseases.
In rare cases, genetic causes are also present, which can then lead to a familial accumulation of thumb saddle joint arthrosis. Women are often more frequently affected by thumb saddle joint arthrosis than men. Therapeutically, anti-inflammatory drugs such as ibuprofen or diclofenac can be given at an early stage of thumb saddle joint arthrosis and provide relief.
Cortisone injections can also relieve the symptoms in the meantime. In the case of strongly increasing and nocturnal complaints, surgery should be considered. There are various surgical methods that have become established over the last few years.
The most commonly used surgical method is resection-suspension arthroplasty, in which a carpal bone (os trapezium) is removed and the thumb is “tied up” in the saddle joint by means of a tendon loop. Afterwards, it is important to immobilize the joint for 4 weeks, as well as a moderate, gradual partial loading until full loading is possible. As an alternative to surgery, special splints or bandages can be worn to reduce the mobility of the thumb saddle joint. Often, however, affected persons feel severely restricted in their daily activities.
