Anatomy, Abdomen and Pelvis, Perineal Body

The perineal body, also referred to as the "central tendon of the perineum," is a fibromuscular structure located in the midline of the perineum (see Image. Female Perineum). The exact location of this structure is the midline at the junction of the anus and urogenital triangle in both female and male individuals. In the male body, the central tendon of the perineum is located between the anus and the bulb of the penis. In contrast, the female body has this structure lying between the anus and the posterior limit of the vulvar orifice.

The perineal body helps strengthen the pelvic floor and provides attachments to the following muscles:

1. Bulbospongiosus: A striated muscle that adheres anterolaterally to the perineal body.

2. Deep transverse perineal muscle: In the male body, this muscle adheres laterally to the perineal body.

3. Compressor urethrae: In the female body, this muscle adheres anteriorly to the perineal body.

4. External anal sphincter: Attaches posterolaterally to the perineal body.

5. Internal anal sphincter: Intermingles with the longitudinal anis muscle (LAM) and adheres posteriorly to the perineal body.

6. External urethral sphincter: Attaches anteriorly to the perineal body.

7. Levator anis muscle: Comprises the internal fibers of the puborectalis muscle and adheres laterally to the perineal body along its whole vertical length.

8. Rectourethralis: A perineal smooth muscle that runs from the LAM laterally to the bulbourethral glands and adheres anterolaterally to the puborectalis muscle.

9. Longitudinal anis muscle: Known as the LAM and strongly attaches anteriorly and anterolaterally to the perineal body and the puborectalis muscle.

Two fascial structures join the perineal body. The superficial perineal fascia and the perineal membrane join the perineal body anteriorly. The rectovaginal septum in female individuals joins the perineal body superiorly. The rectoprostatic septum in male individuals also attaches to the perineal body superiorly.

The perineal body is critical for maintaining the integrity of the pelvic floor, especially in female persons. The perineal body may rupture during vaginal delivery, potentially widening the gap between the free borders of the levator muscles on both sides. Such a gap predisposes women to prolapse of the rectum, uterus, and, sometimes, the urinary bladder. The perineal body is also an important landmark during the surgical resection of anorectal tumors, ensuring the achievement of a tumor-free circumferential resection margin and reducing the risk of local recurrence.