Functional morphology of the deep transverse metacarpal ligament.

The deep transverse metacarpal ligament extends in radio-ulnar direction between the palmar plates of the metacarpo-phalangeal joints of the second through fifth finger rays. Continuing along the path of the palmar plates, the ligament divides the spaces between the fingers at the metacarpo-phalangeal border into functional spaces bordered by the ligamentous apparatus of the metacarpophalangeal joint capsules and filled by blood-vessels, nerves and intrinsic hand muscles. Morphometric examinations of the deep transverse metacarpal ligament indicate a greater strain of the radial components between the index and middle finger in the transverse plane as well as an increased stressing of sagittal fiber plates connecting the extending apparatus with the deep transverse metacarpal ligament via the metacarpophalangeal force nucleus. Palmar, sagittally directed collagen fiber bundles representing a location of initial or recurrent connective tissue proliferation can be histologically demonstrated as a connection between peritendinous and perivascular connective tissue of the palmar interdigital space and the palmar aponeurosis.