MORPHOLOGIC REGIONS OF THE MULTITENDONED EXTRINSIC FINGER MUSCLES IN THE MONKEY FOREARM

The macaque multitendoned extrinsic finger muscles - extensor digitoru m communis, extensor digitorum quarti et quinti proprius, extensor dig itorum secundi et tertii proprius, flexor digitorum superficialis and flexor digitorum profundus (FDP) - were studied to define their muscle fiber architecture, tendon structures, endplate bands and patterns of external and internal nerve branching. Muscle fiber architecture was then used to define regions in each muscle that might represent functi onal subdivisions. Only in the FDP were these regions innervated by pr imary nerve branches characteristic of neuromuscular compartments.