Topic: Pelvis and inguinal region
Question: Describe pelvic diaphragm. Write in brief about it’s a plate anatomy.
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The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus muscle, and associated connective tissue which span the area underneath the pelvis.
The pelvic diaphragm is a muscular sheet that forms the inferior boundary of the pelvic cavity. It includes:
1. Levator ani muscles: Formed by the pubococcygeus, iliococcygeus and coccygeus muscles. They attach to the inner surface of the pelvis, support pelvic viscera and contribute to the pelvic floor.
2. Coccygeus muscle: Attaches the coccyx to the sacrum and ischial spine. Pulls the coccyx forward during defecation or childbirth.
The levator ani muscles form the largest and most important part of the pelvic diaphragm. They have three origins:
1. Pubic bone: Pubococcygeus portion attaches to back of pubic bone. Forms anterior portion of levator ani.
2. Tendinous arch: Also attaches pubococcygeus medially. Extends from pubic to sacrospinous ligament.
3. Sacrospinous ligament: Iliococcygeus portion attaches to sacrospinous ligament laterally. Forms lateral muscular sling.
The levator ani inserts into the perineal body, perineal membrane, rectum, vagina and coccyx. Through these attachments, it supports the abdominopelvic contents and contributes to fecal, urinary and reproductive continence.
The pelvic diaphragm provides a muscular framework for the abdominopelvic cavity and serves many important functions:
1. Supports pelvic viscera: Bladder, rectum, reproductive organs.
2. Maintains fecal and urinary continence.
3. Important in normal sexual function and childbirth. Relaxes during vaginal delivery to allow passage of fetus.
4. Forms the pelvic floor along with connective tissue and fascia. Weakening can lead to pelvic organ prolapse.
5. Provides attachment points for muscles of the hip and urogenital diaphragms.
6. Separates the pelvic cavity from the perineum below.
In summary, the pelvic diaphragm is formed by the levator ani and coccygeus muscles. It separates and provides support to the abdominopelvic cavity, viscera and pelvic floor. It plays an essential role in many functions including continence, reproduction and childbirth. Damage or weakening can lead to major dysfunction, so maintaining its integrity is important.
