Intramedullary structure of human metacarpals

Area of Science:

• Orthopedic surgery
• Anatomy
• Biomedical engineering

Background:

• Intramedullary fixation is a common orthopedic procedure.
• Understanding bone morphology is critical for device design.

Purpose of the Study:

• To investigate the morphometric characteristics of the metacarpal intramedullary canal.
• To provide data for improved intramedullary device design.

Main Methods:

• External and internal measurements of metacarpal bones from 25 Caucasian cadaver hands.
• Analysis of intramedullary canal shape, cortical thickness, and diameter.

Main Results:

• Significant variations in intramedullary canal shape and dimensions across all five metacarpals.
• Volar cortical wall was approximately 20% thicker than the dorsal cortex.
• No significant radial-ulnar cortical thickness difference, except in the thumb.

Conclusions:

• Metacarpal intramedullary canal morphology is highly variable.
• Canal shape and dimensions must be considered in the design of intramedullary fixation devices and prostheses.