Background The two articular surfaces of the distal ulna get an important role in load transmission and stabilization of the distal radio‐ulnar joint. The present study describes the morphology of the distal radio‐ulnar joint surfaces in terms of the functional relationships between the shape of the ulnar articular facets and the predominant contact situation in this joint. Methods Besides macroscopic dissection and radiological investigation the model of the “inclined plane” has been used to simulate force transmission across the radio‐ulnar joint concerning the angle between the distal and the radial articular surfaces of the ulnar head. Results The presented morphological parameters of the radio‐ulnar joint surfaces verify that the transmitted forces are effective in both a radio‐ulnar and an axial direction. The protection and the captaincy of this joint are limited by its great mobility. The investigations show that signs of an increased load pressure are frequently found in the joints that also show degenerative changes. As a morphological sign of the force transmission, distinct spongious trabecles are formed perpendicularly to the articular circumference in those ulnar heads that show a stolid angle between their articular facets. Conclusions Because of the individuality of the morphological data only qualitative statements can be made both the predominant shapes of the ulnar head, in particular about the loading of its articular surfaces. The angle between its two articular facets influences the force transmission through the radio‐ulnar joint as well as the spongious architecture of the subchondral bone of the ulnar head. © Wiley‐Liss, Inc.

Although the clinical and functional importance of gliding and connective tissue spaces has been repeatedly emphasized (e.g. their role in the spreading of suppurative phlegmonic inflammation) only few literary findings can be presented dealing with the connective tissue spaces in the finger in the metacarpo-phalangeal transition region. Three separate gliding spaces of the finger above the dorsal aponeurosis and their various regional connections can be displayed by means of a plastic injection technique followed by plastination and production of sectional series. These gliding spaces were also examined on fixed and unfixed hands using plastic injection and subsequent dissection. A space was depicted between the proximal interphalangeal joint and the insertion of the dorsal aponeurosis on the distal phalanx of the finger, as well as a further bursa-like space over the proximal interphalangeal joint. A third space was also depicted between the metacarpophalangeal joint and the proximal interphalangeal joint, which displays a variable connection to the gliding canal of the respective extensor tendons. Methodical, functional and clinical aspects will be discussed.

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Pathological changes of wrist bones and ligaments after radial fracture loco typico induce permanent functional restriction and pain. In this paper the effects of malunion on the distal radioulnar joint are investigated and osteotomic therapy of Kienböck's disease gets a new evaluation. By simulating radial malunions on anatomic forearm specimen the effects of these malunions on the contact area during supination, neutral position and pronation are measured. Isolated posttraumatic radial shortening as well as epiphyseal inclination and torsion cause a reduction of radioulnar contact. During supination and pronation the loss of radioulnar contact increases. Most significant reduction of contact takes place at a lower graduation of radial malunion. Pronatory torsion of distal radius compensates for a radioulnar contact reduction from combining dorsal inclination with radial shortening. One conclusion of this paper is an exact restitution of anatomical relations between ulnar head and radial notch after fracture of the distal radius.

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