Background: Ideal fixation for metacarpal fracture should provide immediate stability to allow early rehabilitation. Locked intramedullary nail may fulfill the need. Metecarpal geometry has to be studied in order to design the locked intramedullary nail.
Objective: To study metacarpal geometry in adult cadaver for locked intramedullary nail design.
Material and Method: Radiographs of metacarpals taken from 50 embalmed adult cadavers were measured for essential parameters for locked intramedullary nail design. Total length, proximal metaphyseal width, distal metaphyseal width, isthmus width and medullary canal width were measured. The parameters were analyzed by descriptive statistic.
Results: The average total lengths were ranged from 44.53 to 65.42 mm. The average metaphyseal widths of metacarpal bone were between 11.42 to 16.42 mm. The average medullary canal widths were between 3.05 to 6.74 mm. The extreme small (less than 3 mm) medullary canals were found in index, middle, ring and small metacarpals.
Conclusion: The results of our study provide crucial preliminary data for locked metacarpal nail design for adult patient.

Keywords: Metacarpal, Metacarpal fracture, Intramedullary nail, Bone geometry