Structure of the Perineal Membrane in Females: Gross and... : Obstetrics & Gynecology (original) (raw)

Original Research

Gross and Microscopic Anatomy

From the 1Division of Anatomical Sciences, 2Department of Obstetrics and Gynecology, and 3Pelvic Floor Research Group, University of Michigan Medical School, Ann Arbor, Michigan.

Supported by the Office for Research on Women's Health's SCOR on Sex and Gender Factors Affecting Women's Health and the National Institute of Child Health and Human Development, grants P50 HD044406 and R01 HD 38665.

Corresponding author: Tamara A. Stein, Anatomical Sciences, 3767 Med Sci II, 0608, University of Michigan Medical School, Ann Arbor, MI 48109-0608; e-mail: [email protected].

Financial Disclosure The authors have no potential conflicts of interest to disclose.

OBJECTIVE:

To re-examine the anatomy of the perineal membrane and its anatomical relationships in whole-pelvis and histologic serial section as well as gross anatomical dissection.

METHODS:

Serial trichrome-stained histologic sections of five female pelvic specimens (0–37 years old) were examined. Specimens included the urethra, perineal membrane, vagina, and surrounding structures. Macroscopic whole-pelvis sections of three adults, 28–56 years of age, in axial, sagittal, and coronal sections were also studied. Dissections of six female cadavers, 48–90 years of age, were also performed.

RESULTS:

The perineal membrane is composed of two regions, one dorsal and one ventral. The dorsal portion consists of bilateral transverse fibrous sheets that attach the lateral wall of the vagina and perineal body to the ischiopubic ramus. This portion is devoid of striated muscle. The ventral portion is part of a solid three-dimensional tissue mass in which several structures are embedded. It is intimately associated with the compressor urethrae and the urethrovaginal sphincter muscle of the distal urethra with the urethra and its surrounding connective. In this region the perineal membrane is continuous with the insertion of the arcus tendineus fascia pelvis. The levator ani muscles are connected with the cranial surface of the perineal membrane. The vestibular bulb and clitoral crus are fused with the membrane's caudal surface.

CONCLUSION: