Search PubMedSearch

PubMed · 2666492

Triangular fibrocartilage complex lesions: a classification.

Abstract

Based on anatomic and biomechanical studies and review of our clinical experience of the past 10 years, a classification of injuries to the triangular fibrocartilage complex is presented. This classification is based on the clinical examination, routine x-ray films, wrist arthrograms, wrist arthroscopy, and wrist arthrotomy. The classification recognizes both traumatic and degenerative lesions. Traumatic lesions are classified according to their location. Degenerative lesions are classified by the location and severity of degenerative changes of the triangular fibrocartilage complex, ulnar head, ulnocarpal bones and lunotriquetral ligament.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A K Palmer. 1989. Triangular fibrocartilage complex lesions: a classification.. https://doi.org/10.1016/0363-5023(89)90174-3

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Learning to write letters: transfer in automated movements indicates modularity of motor programs in human subjects.

Many automatic movements are open-loop, feed-forward motor programs (MP) that are kinematically well characterized by smooth speed and acceleration curves. However, it is unclear whether their internal representation consists of monolithic blocks or subroutines. This question was investigated using a learning paradigm of a writing task. Fifty-nine normal subjects were presented with two similar, but different new letters. Every subject practiced each letter in a series of 60 trials, with the order of letter series randomized. Every session was continuously recorded by a digitizing tablet. Using kinematic analysis, we measured the number of vertical acceleration peaks as an indication of the number of corrective movements (COM). Since COM declined as automatization was approached, we could quantitatively infer progress in motor learning under natural learning conditions. In the case of modular storage of MP, transfer in-between letters was expected due to the re-use of pre-learned motor subroutines. Statistical analysis showed that the exponential model described the data much better than the linear model (residual error: P<0.88 and P<0.00001, respectively), as expected for a learning paradigm. There was no difference between letters per se (P<0.77). Motor improvement differed significantly (P<0.02) between the first and the second series; there was a much greater reduction of COM in the second series (50.1 vs. 41.1%). This difference can be logically ascribed to transfer, indicating that automated movements are stored in motor subroutines.

Biomechanical Phenomena

The control of human locomotor pointing under restricted informational conditions.

Since a perception-action coupling type of control (Kugler, P.N. and Turvey, M.T., Information, Natural Law, and Self-Assembly of Rhythmic Movements, Erlbaum, Hillsdale, 1987, 481 pp.) continuously operates during locomotor pointing tasks (e.g. long jumping) (Montagne, G., Cornus, S., Glize, D., Quaine, F. and Laurent, M., A 'perception-action coupling' type of control in long-jumping. J. Motor Behav., (2000) in press), the information sources underlying this control have to be dealt with. Under the assumption that subjects use information about the first-order time remaining before they pass the target, we identify in the literature four different sources of information that specify this physical property. Only one of these sources is inevitably present under all possible environmental conditions containing at least a continuously visible target on the floor. This study aimed to test its sufficiency to perform a locomotor pointing task. The use of a virtual reality set-up permitted us to compare locomotor pointing executed with all four information sources or only with the aforementioned one. The likeness found between those two conditions, as far as the pointing performance and the mode of control are concerned, expresses the evoked sufficiency.

Biomechanical Phenomena

The elasticity and failure of fluid-filled cellular solids: theory and experiment.

We extend and apply theories of filled foam elasticity and failure to recently available data on foods. The predictions of elastic modulus and failure mode dependence on internal pressure and on wall integrity are borne out by photographic evidence of distortion and failure under compressive loading and under the localized stress applied by a knife blade, and by mechanical data on vegetables differing only in their turgor pressure. We calculate the dry modulus of plate-like cellular solids and the cross over between dry-like and fully fluid-filled elastic response. The bulk elastic properties of limp and aging cellular solids are calculated for model systems and compared with our mechanical data, which also show two regimes of response. The mechanics of an aged, limp beam is calculated, thus offering a practical procedure for comparing experiment and theory. This investigation also thereby offers explanations of the connection between turgor pressure and crispness and limpness of cellular materials.

Biomechanical Phenomena