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.eduDiagram at southwest.tn.edu* – "The Male Pelvis: Articulated bones of male pelvis"
*
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Pelvis