The pelvic inlet or superior aperture 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 ...

is a planar surface which defines the boundary between the

pelvic cavity 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 the reproducti ...

and 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 the th ...

(or, according to some authors, between two parts of the pelvic cavity, called lesser pelvis and greater pelvis). It is a major target of measurements of

pelvimetry Pelvimetry is the measurement of the female pelvis. It can theoretically identify cephalo-pelvic disproportion, which is when the capacity of the pelvis is inadequate to allow the fetus to negotiate the birth canal. However, clinical evidence indi ...

. Its position and orientation relative to the skeleton of the pelvis is anatomically defined by its edge, the

pelvic brim The pelvic brim is the edge of the pelvic inlet. It is an approximately Mickey Mouse head-shaped line passing through the prominence of the sacrum, the arcuate and pectineal lines, and the upper margin of the pubic symphysis. Structure The pel ...

. The pelvic brim is an approximately apple-shaped line passing through the prominence of the

sacrum The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part ...

, the

arcuate ''Arcuate'' (Latin for "curved") can refer to: Anatomy * Arcuate fasciculus * Arcuate line (disambiguation) * Arcuate artery (disambiguation), several arteries * Arcuate nucleus * Arcuate nucleus (medulla) * Arcuate ligaments of the diaphragm * A ...

and pectineal lines, and the upper margin of the

pubic symphysis The pubic symphysis is a secondary cartilaginous joint between the left and right superior rami of the pubis of the hip bones. It is in front of and below the urinary bladder. In males, the suspensory ligament of the penis attaches to the pubi ...

. Occasionally, the terms pelvic inlet and pelvic brim are used interchangeably.

Boundaries

The edge of the pelvic inlet (pelvic brim) is formed as follows:

Diameters

The diameters or conjugates of the pelvis are measured at the pelvic inlet and outlet and as oblique diameters. Two diameters may be measured from the outside of the body using a pelvimeter

Additional images

Skeletal pelvis-pubis.svg, Pelvis Konjugata vera.jpg, Conjugata vera as measured on sagittal MRI File:Low-dose CT of transverse diameter of pelvic inlet.jpg, Low-dose CT scan of the transverse diameter of the pelvic inlet, as part of

File:Low-dose CT of obstetric conjugate.jpg, Obstetric conjugate, as a measure of the pelvic inlet in the

sagittal plane The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse and coronal planes. The plane may be in the center of the body and divid ...

External links

* * - transverse diameter is blue pipecleaner, anteroposterior or conjugate diameter is red pipecleaner
Image at mun.ca
* (, ) {{Authority control Pelvis

Boundaries

Diameters

Additional images

See also

External links