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The pelvic cavity is a
body cavity A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid. The two largest human body cavities are the ventral body cavity, and ...
that is bounded by the bones of the
pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...
. Its oblique roof is the
pelvic inlet The pelvic inlet or superior aperture of the pelvis is a planar surface which defines the boundary between the pelvic cavity and the abdominal cavity (or, according to some authors, between two parts of the pelvic cavity, called lesser pelvis an ...
(the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reproductive organs,
urinary bladder The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine ente ...
, distal ureters, proximal
urethra The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra ...
, terminal
sigmoid colon The sigmoid colon (or pelvic colon) is the part of the large intestine that is closest to the rectum and anus. It forms a loop that averages about in length. The loop is typically shaped like a Greek letter sigma (ς) or Latin letter S (thus ' ...
,
rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the sigmoid colon) at the l ...
, and anal canal. In females, the
uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...
,
Fallopian tube The fallopian tubes, also known as uterine tubes, oviducts or salpinges (singular salpinx), are paired tubes in the human female that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In o ...
s,
ovaries The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...
and upper
vagina In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...
occupy the area between the other viscera. The
rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the sigmoid colon) at the l ...
is located at the back of the pelvis, in the curve of the sacrum and coccyx; the bladder is in front, behind the pubic 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, or
childbirth Childbirth, also known as labour and delivery, is the ending of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million births glob ...
might damage the pudendal nerves and later lead to anal weakness.


Structure

The pelvis has an anteroinferior, a posterior, and two lateral pelvic walls; and an inferior pelvic wall, also called the pelvic floor. The parietal peritoneum is attached here and to the abdominal wall.


Lesser pelvis

The lesser pelvis (or "true pelvis") is the space enclosed by the pelvic girdle and below the pelvic brim: between the
pelvic inlet The pelvic inlet or superior aperture of the pelvis is a planar surface which defines the boundary between the pelvic cavity and the abdominal cavity (or, according to some authors, between two parts of the pelvic cavity, called lesser pelvis an ...
and the pelvic floor. This cavity is a short, curved canal, deeper on its posterior than on its anterior wall. Some sources consider this region to be the entirety of the pelvic cavity. Other sources define the pelvic cavity as the larger space including the greater pelvis, just above the pelvic inlet. The lesser pelvis is bounded in front and below by the superior 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 the ischium, and the part of the ilium below the arcuate line. The lesser pelvis contains the pelvic colon,
rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the sigmoid colon) at the l ...
,
bladder The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine en ...
, and some of the sex organs. The rectum is at the back, in the curve of the sacrum and coccyx; the bladder is in front, behind the pubic symphysis. In females, the
uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...
and
vagina In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...
occupy the interval between these viscera. The
pelvic splanchnic nerves Pelvic splanchnic nerves or nervi erigentes are splanchnic nerves that arise from sacral spinal nerves S2, S3, S4 to provide parasympathetic innervation to the organs of the pelvic cavity. Structure The pelvic splanchnic nerves arise from th ...
arising at S2–S4 are in the lesser pelvis.


Greater pelvis

The greater pelvis (or false pelvis) is the space enclosed by the pelvic girdle above and in front of the pelvic brim. It is bounded on either side by the ilium. In the front, it is incomplete, presenting a wide interval between the anterior borders of the ilia, which is filled by the muscles and fascia of the anterior abdominal wall; behind is a deep notch on either side between the ilium and the base of the sacrum that is filled by the thoracolumbar fascia and associated muscles. It is generally considered part of the
abdominal cavity The abdominal cavity is a large body cavity in humans and many other animals that contains many organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roof is th ...
(which is why it is sometimes called the false pelvis).Drake et al. (2009) Grays Anatomy for Students, 2nd Edition, ch. 5 ''Pelvis and perineum'' – ''general description'', p. 406 Some sources consider this region part of the pelvic cavity, while others reframe the classification by calling the combination the abdominopelvic cavity. The greater pelvis supports the intestines (specifically, the ileum and
sigmoid colon The sigmoid colon (or pelvic colon) is the part of the large intestine that is closest to the rectum and anus. It forms a loop that averages about in length. The loop is typically shaped like a Greek letter sigma (ς) or Latin letter S (thus ' ...
), and transmits part of their weight to the anterior wall of the
abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...
. The femoral nerve from L2–L4 is in the greater pelvis, but not in the lesser pelvis.


Ligaments


Arteries

*
internal iliac artery The internal iliac artery (formerly known as the hypogastric artery) is the main artery of the pelvis. Structure The internal iliac artery supplies the walls and viscera of the pelvis, the buttock, the reproductive organs, and the medial comp ...
* median sacral artery *
ovarian artery The ovarian artery is an artery that supplies oxygenated blood to the ovary in females. It arises from the abdominal aorta below the renal artery. It can be found within the suspensory ligament of the ovary, anterior to the ovarian vein and uret ...


Nerves

* sacral plexus *
splanchnic nerves The splanchnic nerves are paired visceral nerves (nerves that contribute to the innervation of the internal organs), carrying fibers of the autonomic nervous system ( visceral efferent fibers) as well as sensory fibers from the organs ( visceral a ...
* femoral nerve ( greater pelvis)


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.


Additional images

File:Gray319.png, Joints of the pelvis. Anterior view. File:Gray539.png, The arteries of the pelvis. File:Gray829.png, Dissection of side wall of pelvis showing sacral and pudendal plexuses. File:Gray837.png, Sacral plexus of the right side. File:Male pelvic cavity.jpg, Male pelvic cavity File:Female pelvic cavity.jpg, Female pelvic cavity File:Scheme body cavities-en.svg, Lateral projection of the human body cavities, with the line separating the abdominal and pelvic cavities shown.


References


External links


Overview at buffalo.edu

Diagram at southwest.tn.edu


* – "The Male Pelvis: Articulated bones of male pelvis" * {{Authority control Pelvis