Origin and insertion points involved in levator ani muscle defects.

OBJECTIVE

This project sought to identify and to describe the anatomical connections affected by levator ani defects involving the pubovisceral portion of the muscle.

STUDY DESIGN

Fourteen magnetic resonance scans of women with unilateral levator defects were selected. The missing muscle mapping technique was used to characterize the absent muscle. Normal muscle was visualized and compared with the contralateral side. Using a three-dimensional slicer, the outline of the intact muscle was traced; models of this muscle and surrounding structures were generated.

RESULTS

The missing muscle originates from the posterior pubic bone and extends laterally over the obturator internus muscle; it inserts into the vaginal wall, perineal body, and the intersphincteric space. Architectural distortion, with an asymmetric lateral spilling of the vagina was present in 50% of women. The defect was right sided in 71% of patients.

CONCLUSION

The origin and insertion points of the damaged portion of the levator ani muscle were identified.