Pelvic inlet
| Bone: Pelvic inlet | |
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| Diameters of superior aperture of lesser pelvis (female). | |
| Latin | apertura pelvis superior |
| Gray's | subject #58 239 |
The pelvic inlet or superior aperture of the pelvis is a planar surface which is typically used to define 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 and greater pelvis).
Its position and orientation relative to the skeleton of the pelvis is anatomically defined by its edge, the pelvic brim. The pelvic brim is an approximately apple-shaped line passing through the prominence of the sacrum, the arcuate and pectineal lines, and the upper margin of the pubic symphysis.
Occasionally, the terms pelvic inlet and pelvic brim are used interchangeably.
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[edit] Boundaries
The edge of the pelvic inlet (pelvic brim) is formed as follows:
| Anteriorly by the pubic crest (or pubic symphysis) |
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| Laterally by the iliopectineal line |
(same as other side) | |
| Posteriorly by the anterior margin of the base of the sacrum (or the ala of sacrum) and sacrovertebral angle (or sacral promontory) |
[edit] Diameters
It has three principal diameters: antero-posterior (conjugate), transverse, and oblique.
| Name | Description | Average measurement in female |
| anteroposterior or conjugate diameter or conjugata vera | extends from the sacrovertebral angle (promontorium) to the pubic symphysis; | about 110 mm. |
| transverse diameter | extends across the greatest width of the superior aperture, from the middle of the brim on one side to the same point on the opposite; | about 135 mm. |
| oblique diameter | extends from the iliopectineal eminence of one side to the sacroiliac articulation of the opposite side; | about 125 mm. |
[edit] Additional images
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Pelvis
[edit] External links
- SUNY Anatomy Image 9951
- SUNY Anatomy Image 9950 - transverse diameter is blue pipecleaner, anteroposterior or conjugate diameter is red pipecleaner
- Image at mun.ca
- pelvis at The Anatomy Lesson by Wesley Norman (Georgetown University) (medialpelvissmall, malepelvissagittalinlet&outletsml)
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