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Greater (False) Pelvis
Greater (false) pelvis is the area above the pelvic brim supporting abdominal viscera.
RegionPelvis and Perineum
System-
The greater pelvis, also known as the false pelvis, is the expanded portion of the pelvic cavity located superior to the pelvic inlet. Unlike the lesser (true) pelvis, which houses pelvic organs, the greater pelvis supports abdominal structures and forms the lower boundary of the abdominal cavity. It is bounded laterally by the iliac fossae and serves as a transition zone between the abdomen and true pelvic cavity. Though not directly involved in reproduction or elimination, the greater pelvis plays a structural and supportive role in posture, locomotion, and abdominal organ positioning.
Structure
The greater pelvis is part of the pelvic cavity above the pelvic brim. It is bounded by bony structures but lacks a floor, merging superiorly with the abdominal cavity.
Boundaries of the Greater Pelvis
| Boundary | Landmark |
|---|---|
| Posterior | Upper sacrum and lumbar vertebrae (L5) |
| Lateral | Iliac fossae and iliac crests |
| Anterior | Lower anterior abdominal wall |
| Inferior | Pelvic brim (marks transition to lesser pelvis) |
| Superior | Continuous with the abdominal cavity |
Location
The greater pelvis is located superior to the pelvic inlet and lies between the iliac wings. It is considered part of the abdominal cavity in functional terms and lacks a complete bony floor. It contains portions of the small intestine (especially ileum), sigmoid colon, and, in females, parts of the uterus and ovaries when they are elevated above the inlet.
Function
- Support for Abdominal Organs: Provides a broad, bony platform for supporting loops of intestines and parts of the sigmoid colon
- Structural Continuity: Acts as a transitional region between the true pelvis and abdominal cavity
- Muscle Attachment: Offers wide surfaces (iliac fossae) for origin of iliacus and abdominal muscles
- Postural Stability: Forms part of the pelvic ring that helps maintain upright posture and transfer loads to the lower limbs
Contents of the Greater Pelvis
| Organ | Notes |
|---|---|
| Small intestine (ileum) | Loops often rest in the greater pelvis when standing |
| Sigmoid colon | Traverses the greater pelvis before entering the true pelvis |
| Ureters | Course through posterior greater pelvis before entering true pelvis |
| Ovaries (female) | May temporarily rise into greater pelvis, especially in young or gravid females |
| Uterus (female) | Normally tilted forward; may lie partially within greater pelvis |
Clinical Significance
- Palpation Reference: The iliac crests that form the superior margin of the greater pelvis are useful surface landmarks for lumbar puncture and pelvic measurements
- Pregnancy: During early pregnancy, the uterus expands into the greater pelvis before descending into the true pelvis during labor
- Obesity and Visceral Compression: Excess fat in the greater pelvis can displace or compress abdominal organs, contributing to GI or urinary symptoms
- Surgical Access: The greater pelvis offers entry for certain laparoscopic and retroperitoneal procedures targeting pelvic or lower abdominal structures
Published on May 9, 2025
Last updated on May 9, 2025
Last updated on May 9, 2025