| Pelvic cavity | |
|---|---|
 The various cavities of the human body as seen in afrontal projection, with the pelvic cavity labeled4. | |
 The various cavities of the human body as seen in alateral projection, with the pelvic cavity labeled4. | |
| Details | |
| Artery | Ovarian artery,internal iliac artery,median sacral artery |
| Vein | Internal iliac vein,internal pudendal vein,vesical vein |
| Nerve | Inferior hypogastric plexus |
| Lymph | Primarilyinternal iliac lymph nodes |
| Identifiers | |
| Latin | cavitas pelvis |
| TA98 | A02.5.02.002 |
| TA2 | 1283 |
| FMA | 9738 |
| Anatomical terminology | |
Thepelvic cavity is abody cavity that is bounded by the bones of thepelvis. Its oblique roof is thepelvic inlet (the superior opening of the pelvis). Its lower boundary is thepelvic floor.
The pelvic cavity primarily contains thereproductive organs,urinary bladder, distalureters, proximalurethra, terminalsigmoid colon,rectum, andanal canal. In females, theuterus,fallopian tubes,ovaries and uppervagina occupy the area between the otherviscera.[1][2]
Therectum is located at the back of the pelvis, in the curve of thesacrum andcoccyx; the bladder is in front, behind thepubic symphysis. The pelvic cavity also contains major arteries, veins, muscles, and nerves. These structures coexist in a crowded space, and disorders of one pelvic component may impact upon another; for example, constipation may overload the rectum and compress the urinary bladder, orchildbirth might damage thepudendal nerves and later lead toanal weakness.
The pelvis has an anteroinferior, a posterior, and two lateral pelvic walls; and an inferior pelvic wall, also called thepelvic floor.[3][4] Theparietal peritoneum is attached here and to theabdominal wall.[5]
The lesser pelvis (or "true pelvis") is the space enclosed by thepelvic girdle and below thepelvic brim: between thepelvic inlet and the pelvic floor. This cavity is a short, curved canal, deeper on its posterior than on its anterior wall.[1] Some sources consider this region to be the entirety of the pelvic cavity. Other sources define the pelvic cavity as the larger space including thegreater pelvis, just above the pelvic inlet.
The lesser pelvis is bounded in front and below by thesuperior rami of the symphysis pubis; above and behind, by the sacrum and coccyx; and laterally, by a broad, smooth, quadrangular area of bone, corresponding to the inner surfaces of the body and superior ramus of theischium, and the part of theilium below thearcuate line.[1]
roof:pelvic brim[6] | ||
| posterior:sacrum,coccyx | lateral:obturator internus | anterior:pubic symphysis |
| floor: pelvic floor | ||
The lesser pelvis contains thepelvic colon,rectum,bladder, and some of thesex organs.The rectum is at the back, in the curve of thesacrum andcoccyx; the bladder is in front, behind thepubic symphysis. In females, theuterus andvagina occupy the interval between these viscera.[1]
Thepelvic splanchnic nerves arising at S2–S4 are in the lesser pelvis.
The greater pelvis (or false pelvis) is the space enclosed by thepelvic girdle above and in front of thepelvic brim. It is bounded on either side by theilium. In the front, it is incomplete, presenting a wide interval between the anterior borders of theilia, which is filled by the muscles and fascia of theanterior abdominal wall; behind is a deep notch on either side between the ilium and thebase of the sacrum that is filled by thethoracolumbar fascia and associated muscles.[1]
It is generally considered part of theabdominal cavity (which is why it is sometimes called the false pelvis).[7] Some sources consider this region part of the pelvic cavity,[citation needed] while others reframe the classification by calling the combination theabdominopelvic cavity.
The greater pelvis supports theintestines (specifically, theileum andsigmoid colon), and transmits part of their weight to the anterior wall of theabdomen.[1]
Thefemoral nerve from L2–L4 is in the greater pelvis, but not in the lesser pelvis.
| Ligament | From | To |
|---|---|---|
| broad ligament of the uterus | uterus | side of pelvis |
| *mesovarium | ovary | |
| *mesosalpinx | Fallopian tube | broad ligament of the uterus |
| *mesometrium | ||
| cardinal ligament | cervix and vagina | pelvic wall |
| ovarian ligament | ovary | uterus |
| round ligament of the uterus | ovary | travels through inguinal canal, ends at mons pubis |
| suspensory ligament of the ovary | ovary | pelvic wall |
The pelvis can be classified into four main types by measuring the pelvic diameters and conjugates at the pelvic inlet and outlet and as oblique diameters.
| Measurement | From | To | Length |
|---|---|---|---|
| Transverse diameter (of inlet) | Between extreme lateral points of pelvic inlet | 13.5–14 cm | |
| Oblique diameter I | Rightsacroiliac joint | Left iliopubic eminence | 12-12.5 cm |
| Oblique diameter II | Left sacroiliac joint | Right iliopubic eminence | 11.5–12 cm |
| Anatomical conjugate (true conjugate) | Pubic symphysis | Promontory | ~12 cm |
| Obstetric conjugate | Retropubic eminence (posterior surface of symphysis) | Promontory | >10 cm |
| Diagonal conjugate* | Inferior pubic ligament | Promontory | 11.5–12 cm |
| Straight conjugate | Lower border of symphysis | Tip of coccyx | 9.5–10 cm |
| Median conjugate | Lower border of symphysis | Lower border of sacrum | 11.5 cm |
| Transverse diameter (of outlet) | Betweenischial tuberosities | 10–11 cm | |
| Interspinous distance | Between anterior superior iliac spines | 26 cm (female) | |
| Intercristal distance | Between furthest lateral points ofiliac crest | 29 cm (female) | |
| External conjugate | Spinous process of fifth lumbar vertebra | Upper edge of symphysis | ~20 cm |
| Intertrochanteric distance | Between femurs | 31 cm | |
| Because the true conjugate cannot be measured directly, it is derived from the diagonal conjugate, which is measured through the vagina. | |||
This article incorporates text in thepublic domain from the 20th edition ofGray's Anatomy(1918)
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