A GENERIC MORPHOLOGICAL MODEL OF THE ANATOMIC VARIABILITY IN THE M-FLEXOR DIGITORUM PROFUNDUS, M-FLEXOR POLLICIS LONGUS AND MM-LUMBRICALES COMPLEX

In the present study a generic model is presented of the anatomic vari ability in the muscle group formed by the m. flexor digitorum profundu s, m. flexor pollicis longus and mm. lumbricales. This model provides a hypothesis about the structural causes of the frequent interdependen ce of tendons and muscle bellies in this muscle group. The model consi ders the muscle group as composed of two simple elementary building bl ocks: the monogastric contractile units of the FDP-FPL, and the digast ric contractile elements of the lumbrical, and shows that these units can be assembled into complex entities, to which in reality a third st ructural element, the synovial membranes, not discussed in the present paper, adds a further complexity. The model allows to generate homolo gues of the existing anatomical variants, which are illustrated by typ ical dissection results. The present study should be of relevance to t he morphologist, embryologist, surgeon, and musician/pedagogue. To the morphologist, it presents an alternative method of description or und erstanding of anatomic variability, based on (i) the 'atomary' concept that the anatomic structure is assembled from simple basic elements, and (ii) the local spatial constraints. To the embryologist, it raises the question to what degree the 'atomary' anatomical components of th is model, which describes the macroscopic anatomy of the muscle group in detail, have an embryological basis. To the surgeon, the study pres ents detailed information about the scope of the variability in the de ep flexor group, and the nature of its intertendinous connections. To the musician/pedagogue, it presents a visual illustration of the conge nital interdependence of the muscles and tendons of an important finge r motor group, as a possible cause of lack in finger independence whic h may hamper a fluent instrumental technique.