Bone: Pelvic outlet
Diameters of inferior aperture of lesser pelvis (female).
Muscles of the female perineum.
Latin	apertura pelvis inferior
Gray's	subject #58 240

The lower circumference of the lesser pelvis is very irregular; the space enclosed by it is named the inferior aperture or pelvic outlet.

Contents 1 Boundaries 2 Notches 3 In situ 4 Additional images 5 External links

[edit] Boundaries

It has the following boundaries:

• anteriorly: the pubic arch
• laterally: the ischial tuberosities
• posterolaterally: the inferior margin of the sacrotuberous ligament
• posteriorly: the tip of the coccyx

[edit] Notches

These eminences are separated by three notches:

• one in front, the pubic arch, formed by the convergence of the inferior rami of the ischium and pubis on either side.
• The other notches, one on either side, are formed by the sacrum and coccyx behind, the ischium in front, and the ilium above; they are called the sciatic notches; in the natural state they are converted into foramina by the sacrotuberous and sacrospinous ligaments.

[edit] In situ

When the ligaments are in situ, the inferior aperture of the pelvis is lozenge-shaped, bounded as follows:

• in front, by the pubic arcuate ligament and the inferior rami of the pubes and ischia
• laterally, by the ischial tuberosities
• behind, by the sacrotuberous ligaments and the tip of the coccyx.

[edit] Additional images

Articulations of pelvis. Anterior view.

Articulations of pelvis. Posterior view.

[edit] External links

• pelvis at The Anatomy Lesson by Wesley Norman (Georgetown University) (medialpelvissmall, malepelvissagittalinlet&outletsml)

v • d • e Bones of pelvis / pelvic cavity (TA A02.5.01-03, GA 2.231-241) General sacrum · coccyx · hip bone Ilium body arcuate line wing gluteal lines (posterior, anterior, inferior) iliac spines (anterior superior, anterior inferior, posterior superior, posterior inferior) other: crest · tuberosity · tubercle · fossa Ischium body ischial spine · lesser sciatic notch superior ramus tuberosity of the ischium inferior ramus no substructures Pubis body pubic crest superior ramus pubic tubercle · obturator crest inferior ramus pectineal line Compound acetabulum (acetabular notch) · iliopubic eminence / iliopectineal line · linea terminalis · ischiopubic ramus / pubic arch obturator foramen · greater sciatic foramen / greater sciatic notch · lesser sciatic foramen lesser pelvis (pelvic inlet, pelvic brim, pelvic outlet) · greater pelvis