Pelvic and Perineal Anatomy Overview

Overview

This lecture provides an overview of the anatomy and key features of the pelvis and perineum, highlighting their structures and clinical relevance.

Anatomy of the Pelvis

• The pelvis is a bony ring formed by the sacrum, coccyx, and two hip bones.
• The pelvis is divided into greater (false) and lesser (true) pelvis.
• The pelvic inlet is the boundary separating the greater and lesser pelvis.
• The sacrum forms the posterior wall of the pelvis, while the pubic symphysis is anterior.
• The pelvic cavity contains reproductive organs, bladder, and rectum.

Pelvic Floor and Muscles

• The pelvic floor is formed mainly by the levator ani and coccygeus muscles.
• The pelvic diaphragm supports pelvic organs and maintains continence.
• Muscles of the pelvic wall include obturator internus and piriformis.

Perineum Structure

• The perineum is the region below the pelvic diaphragm between the thighs.
• The perineum is divided into urogenital and anal triangles.
• The urogenital triangle contains external genitalia and openings of the urinary and reproductive tracts.
• The anal triangle contains the anus and surrounding tissues.

Clinical Considerations

• Weakness of pelvic floor muscles can lead to prolapse or incontinence.
• The perineal body is a central tendon important for childbirth and continence.
• Injury to perineal structures may occur during childbirth or trauma.

Key Terms & Definitions

• Pelvis — Bony structure at the base of the spine, enclosing the pelvic cavity.
• Pelvic diaphragm — Muscular floor of the pelvis supporting the organs.
• Perineum — Area between the thighs, below the pelvic diaphragm.
• Levator ani — Major muscle group of the pelvic floor.
• Urogenital triangle — Anterior part of the perineum, housing genital and urinary openings.
• Anal triangle — Posterior part of the perineum, containing the anus.

Action Items / Next Steps

• Review diagrams of pelvic and perineal anatomy.
• Memorize key muscle groups and their functions.
• Prepare for questions on pelvic floor disorders and perineal trauma.