Pelvic cavity

Pelvic cavity
Details
Lymph	primarily internal iliac lymph nodes
Identifiers
Latin	cavitas pelvis
TA98	A02.5.02.002
TA2	1283
FMA	9738
Anatomical terminology

The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor.

The pelvic cavity primarily contains reproductive organs, the urinary bladder, the pelvic colon, and the rectum. The rectum is placed at the back of the pelvis, in the curve of the sacrum and coccyx; the bladder is in front, behind the pubic symphysis. In the female, the uterus and vagina occupy the interval between these viscera. The pelvic cavity also contains major arteries, veins, muscles, and nerves. These structures have to work together in a little crowded space. They can be affected by many different diseases and by many drugs in many different ways. One part may impact upon another, for example constipation may overload the rectum and compress the urinary bladder, or childbirth might damage the pudendal nerves and later lead to anal weakness. And that is not a fun problem.

Borders

The boundaries are as follows:

	roof: pelvic brim
posterior: sacrum, coccyx	lateral: obturator internus	anterior: pubic symphysis
	floor: pelvic floor

Greater and lesser pelvis

The lesser pelvis (or "true" pelvis) only includes structures inferior to the pelvic brim.

For example, the pelvic splanchnic nerves arising at S2-S4 is in the true pelvis, but the femoral nerve from L2-L4 is only in the "false pelvis", or greater pelvis.

Ligaments

Ligament	From	To
broad ligament of the uterus
* mesovarium	ovary
* mesosalpinx	Fallopian tube
* mesometrium
cardinal ligament
ovarian ligament	ovary	uterus
round ligament of the uterus
suspensory ligament of the ovary

Measurements

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.

Pelvic measurements

Measurement	From	To	Length
Transverse diameter (of inlet)	Between extreme lateral points of pelvic inlet		13.5-14 cm
Oblique diameter I	Right sacroiliac joint	Left iliopubic eminence	12-12.5 cm
Oblique diameter II	Left sacroiliac joint	Right iliopubic eminence	11.5-12 cm
Anatomical conjugate	Pubic symphysis	Promontory	~12 cm
True conjugate (obsteric conjugate)	Retropubic eminence (posterior surface of symphysis)	Promontory	11.5 cm
Diagonal conjugate*	Inferior pubic ligament	Promontory	13 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)	Between ischial tuberosities		10-11 cm
Interspinous distance	Between anterior superior iliac spines		26 cm (female)
Intercristal distance	Between furthest lateral points of iliac 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 can not be measured directly it is derived from the diagonal conjugate which is measured through the vagina.

Arteries

• internal iliac artery
• median sacral artery
• ovarian artery

Nerves

• sacral plexus
• splanchnic nerves

Additional images

• 
• 
  Articulations of pelvis. Anterior view.
• 
  The arteries of the pelvis.
• 
  Dissection of side wall of pelvis showing sacral and pudendal plexuses.
• 
  Sacral plexus of the right side.

References

• Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol. 1: Locomotor System (5th ed.). Thieme. ISBN 3-13-533305-1.

External links

• Overview at buffalo.edu
• Diagram at southwest.tn.edu
• Photo of model (female)