Muscles of pelvic floor:perineum

Muscles of the Pelvic Floor and Perineum

• The pelvic floor is a muscular sheet that defines the lower portion of the pelvic cavity.

  • Formed by the pelvic diaphragm from the pubis to the coccyx.

  • Key muscles include the levator ani and ischiococcygeus.

  • These muscles create openings for the anal canal, urethra, and vagina in females.

1. Levator Ani: The Pillar of Support

• Comprises two muscles: pubococcygeus and iliococcygeus.

  • Fundamental for pelvic floor function.

  • Supports pelvic viscera and resists intra-abdominal pressure.

  • Directs pressure toward the colon for defecation and uterus during childbirth.

  • Forms sphincters at the urethra and anus, aiding continence.

• Figure 1: Shows the anatomical locations of the levator ani and ischiococcygeus, emphasizing their role in pelvic support.

2. Perineum: The Diamond-Shaped Space

• Located below the pelvic diaphragm.

• Shaped like a diamond, bordered by:

  • Pubic symphysis (anteriorly)

  • Coccyx (posteriorly)

  • Ischial tuberosities (laterally)

• Divided into two triangles:

  • Urogenital triangle (anterior): Houses external genitals.

  • Anal triangle (posterior): Encompasses the anus.

• Figure 2: Diagrams the perineum's organization and functions.

Layers and Distinctions

• The perineum is divided into superficial and deep layers, each with roles common to all sexes.

  • Superficial Muscles include:

    • Levator ani: Resists abdominal pressure and aids in defecation.

    • Bulbospongiosus: Supports the perineal body and assists in sexual functions.

  • Deep Muscles include:

    • Ischiocavernosus: Compresses urethra and maintains erections.

    • External urethral sphincter: Controls urination.

    • External anal sphincter: Controls defecation.

• Understanding the pelvic floor's complexity provides insights into various bodily functions.

Table 1: Muscles of the Perineum Common to All Humans

• Highlights muscle roles in functions like defecation, urination, and childbirth.

• Important for maintaining genital structures and controlling sphincters.

Terms to Know

• Ejaculation: The process of expelling semen from the male reproductive tract, typically during sexual climax.

• Anal Triangle: The posterior portion of the perineum that includes the anus and related structures.

Additional Resource

• Consider watching the video on the muscles of the pelvic floor for a visual understanding of these muscle groups.