The chiasma of the flexor digitorum superficialis tendon.

Forty cadaver hands (160 fingers) were dissected to study the morphology and variations of the chiasma of the flexor digitorum superficialis tendon. Ten types of chiasma were noted. One chiasma did not fit into any of the patterns. The long and ring fingers had a very similar distribution of types of chiasma but the index and small both had different patterns. The length of chiasma showed a marked variability which appeared to be independent of phalangeal length.