Distribution of Sesamoid Bones in the Hand—A Study in the Chinese Population

Abstract

Objective To report the prevalence and distribution of hand sesamoid bones in Chinese ethnic group and its left-right symmetry. Methods A retrospective study involving hand radiographs taken in patients admitted to United Christian Hospital from January 2011 to June 2014. Exclusion criteria included previous hand fracture, inadequate radiological views and those of non-Chinese ethnic group. Results A total of 307 hand radiographs (162 left and 145 right; 181 males and 126 females) in 266 patients were reviewed. Bilateral hand radiographs were available in 41 patients. Their mean age (± standard deviation) was 48.8 ± 11.3 years (range, 25–69 years). The total number of sesamoid bones identified was 1,641. Sesamoid bones were found at the first metacarpophalangeal joint (MCPJ) at a rate of 100%, while the prevalence at the second MCPJ, third MCPJ, fourth MCPJ, fifth MCPJ as well as the first interphalangeal joint (IPJ) was 59.0%, 2.93%, 0%, 47.6% and 28.0%, respectively. Bilateral hand radiographs showed 100% symmetrical distribution of sesamoid bones on right and left sides. Conclusion This is the first study in Hong Kong to report prevalence of sesamoid bones in the Chinese Population and identify the symmetry of sesamoid bones in bilateral hands. The result revealed that the Chinese ethnic group had a higher prevalence of sesamoid bones at the 2nd and 3rd MCPJ when compared with other ethnic groups. The distribution of sesamoid bones was symmetrical in bilateral hands.