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.

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