A comparative study of the sonographic appearance and anatomy of the obturator internus in normal males.

The aim of this study was to compare the appearance of the normal male obturator internus on transrectal ultrasound with anatomical examination to advance the knowledge of the male pelvic muscles. This information may help to provide a new imaging method for observation of the normal male obturator internus and may facilitate the treatment of obturator internus abscesses and various other types of interventional therapies. Ten formalin-fixed male cadavers were dissected to examine the appearance and structure of the obturator internus and its relationship with the structures in close proximity. The obturator internus was also observed in five fresh male cadavers using transrectal ultrasound, after which the anatomy of the muscle was confirmed by dissection and its thickness measured. The visible fusiform was observed by sonography. The measurements of obturator internus thickness were 13.33 ± 0.32 mm on the right and 13.41 ± 0.26 mm on the left; in the formalin-fixed fresh cadaver, the measurements were 13.16 ± 0.21 mm on the right and 13.17 ± 0.22 mm on the left. Using transrectal ultrasound to recognize and observe the obturator internus is a new imaging method that will provide a foundation for the recognition of its abnormalities in the future.