Pelvic inlet
From Wikipedia, the free encyclopedia
| Pelvic inlet | |
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| Diameters of superior aperture of lesser pelvis (female). | |
| Latin | apertura pelvis superior |
| Gray's | subject #58 239 |
| Dorlands/Elsevier | a_51/12144724 |
The superior circumference of the lesser pelvis forms the brim of the pelvis, the included space being called the superior aperture or pelvic inlet.
The superior aperture is somewhat heart-shaped, obtusely pointed in front, diverging on either side, and encroached upon behind by the projection forward of the promontory of the sacrum.
The edge of the inlet is known as the pelvic brim. Occasionally, the terms are used interchangeably.
[edit] Boundaries
It is formed as follows:
- laterally: by the pectineal and arcuate lines
- in front: by the crests of the pubes (or pubic symphysis)
- behind: 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, transverse, and oblique.
| Name | Description | Average measurement in female |
| anteroposterior or conjugate diameter | extends from the sacrovertebral angle to the symphysis pubis; | 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] 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
- Norman/Georgetown pelvis (medialpelvissmall, malepelvissagittalinlet&outletsml)
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| Ilium: Arcuate line - Wing - gluteal lines (Posterior, Anterior, Inferior) - Fossa - Tuberosity - Crest - iliac spines (Anterior superior - Anterior inferior - Posterior superior - Posterior inferior)
Ischium: Body (Ischial spine, Lesser sciatic notch) - Superior ramus (Tuberosity of the ischium) - Inferior ramus Pubis: Superior ramus (Pubic tubercle, Pubic crest, Obturator crest) - Inferior ramus (Pectineal line) Compound: Obturator foramen - Acetabulum - Acetabular notch - Greater sciatic notch - Iliopectineal eminence - Ischiopubic ramus - Pubic arch - Lesser pelvis (Pelvic inlet, Pelvic brim, Pelvic outlet) - Greater pelvis |
